Shades of green / red on DA blocks

Allow OP_0 in multisig scripts

backend/README.md

@@ -77,7 +77,7 @@ Query OK, 0 rows affected (0.00 sec)
 
 #### Build
 
-_Make sure to use Node.js 16.10 and npm 7._
+_Make sure to use Node.js 20.x and npm 9.x or newer_
 
 _The build process requires [Rust](https://www.rust-lang.org/tools/install) to be installed._
 

backend/package-lock.json

@@ -1,18 +1,19 @@
 {
   "name": "mempool-backend",
-  "version": "3.0.0",
+  "version": "3.1.0-dev",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "mempool-backend",
-      "version": "3.0.0",
+      "version": "3.1.0-dev",
       "hasInstallScript": true,
       "license": "GNU Affero General Public License v3.0",
       "dependencies": {
+        "@babel/core": "^7.25.2",
         "@mempool/electrum-client": "1.1.9",
         "@types/node": "^18.15.3",
-        "axios": "~1.7.2",
+        "axios": "~1.7.4",
         "bitcoinjs-lib": "~6.1.3",
         "crypto-js": "~4.2.0",
         "express": "~4.19.2",
@@ -2277,9 +2278,9 @@
       }
     },
     "node_modules/axios": {
-      "version": "1.7.2",
-      "resolved": "https://registry.npmjs.org/axios/-/axios-1.7.2.tgz",
-      "integrity": "sha512-2A8QhOMrbomlDuiLeK9XibIBzuHeRcqqNOHp0Cyp5EoJ1IFDh+XZH3A6BkXtv0K4gFGCI0Y4BM7B1wOEi0Rmgw==",
+      "version": "1.7.4",
+      "resolved": "https://registry.npmjs.org/axios/-/axios-1.7.4.tgz",
+      "integrity": "sha512-DukmaFRnY6AzAALSH4J2M3k6PkaC+MfaAGdEERRWcC9q3/TWQwLpHR8ZRLKTdQ3aBDL64EdluRDjJqKw+BPZEw==",
       "dependencies": {
         "follow-redirects": "^1.15.6",
         "form-data": "^4.0.0",
@@ -9438,9 +9439,9 @@
       "integrity": "sha512-+H+kuK34PfMaI9PNU/NSjBKL5hh/KDM9J72kwYeYEm0A8B1AC4fuCy3qsjnA7lxklgyXsB68yn8Z2xoZEjgwCQ=="
     },
     "axios": {
-      "version": "1.7.2",
-      "resolved": "https://registry.npmjs.org/axios/-/axios-1.7.2.tgz",
-      "integrity": "sha512-2A8QhOMrbomlDuiLeK9XibIBzuHeRcqqNOHp0Cyp5EoJ1IFDh+XZH3A6BkXtv0K4gFGCI0Y4BM7B1wOEi0Rmgw==",
+      "version": "1.7.4",
+      "resolved": "https://registry.npmjs.org/axios/-/axios-1.7.4.tgz",
+      "integrity": "sha512-DukmaFRnY6AzAALSH4J2M3k6PkaC+MfaAGdEERRWcC9q3/TWQwLpHR8ZRLKTdQ3aBDL64EdluRDjJqKw+BPZEw==",
       "requires": {
         "follow-redirects": "^1.15.6",
         "form-data": "^4.0.0",

backend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mempool-backend",
-  "version": "3.0.0",
+  "version": "3.1.0-dev",
   "description": "Bitcoin mempool visualizer and blockchain explorer backend",
   "license": "GNU Affero General Public License v3.0",
   "homepage": "https://mempool.space",
@@ -42,7 +42,7 @@
     "@babel/core": "^7.25.2",
     "@mempool/electrum-client": "1.1.9",
     "@types/node": "^18.15.3",
-    "axios": "~1.7.2",
+    "axios": "~1.7.4",
     "bitcoinjs-lib": "~6.1.3",
     "crypto-js": "~4.2.0",
     "express": "~4.19.2",

backend/src/api/audit.ts

@@ -2,6 +2,7 @@ import config from '../config';
 import logger from '../logger';
 import { MempoolTransactionExtended, MempoolBlockWithTransactions } from '../mempool.interfaces';
 import rbfCache from './rbf-cache';
+import transactionUtils from './transaction-utils';
 
 const PROPAGATION_MARGIN = 180; // in seconds, time since a transaction is first seen after which it is assumed to have propagated to all miners
 
@@ -15,7 +16,8 @@ class Audit {
     const matches: string[] = []; // present in both mined block and template
     const added: string[] = []; // present in mined block, not in template
     const unseen: string[] = []; // present in the mined block, not in our mempool
-    const prioritized: string[] = []; // higher in the block than would be expected by in-band feerate alone
+    let prioritized: string[] = []; // higher in the block than would be expected by in-band feerate alone
+    let deprioritized: string[] = []; // lower in the block than would be expected by in-band feerate alone
     const fresh: string[] = []; // missing, but firstSeen or lastBoosted within PROPAGATION_MARGIN
     const rbf: string[] = []; // either missing or present, and either part of a full-rbf replacement, or a conflict with the mined block
     const accelerated: string[] = []; // prioritized by the mempool accelerator
@@ -133,23 +135,7 @@ class Audit {
       totalWeight += tx.weight;
     }
 
-
-    // identify "prioritized" transactions
-    let lastEffectiveRate = 0;
-    // Iterate over the mined template from bottom to top (excluding the coinbase)
-    // Transactions should appear in ascending order of mining priority.
-    for (let i = transactions.length - 1; i > 0; i--) {
-      const blockTx = transactions[i];
-      // If a tx has a lower in-band effective fee rate than the previous tx,
-      // it must have been prioritized out-of-band (in order to have a higher mining priority)
-      // so exclude from the analysis.
-      if ((blockTx.effectiveFeePerVsize || 0) < lastEffectiveRate) {
-        prioritized.push(blockTx.txid);
-        // accelerated txs may or may not have their prioritized fee rate applied, so don't use them as a reference
-      } else if (!isAccelerated[blockTx.txid]) {
-        lastEffectiveRate = blockTx.effectiveFeePerVsize || 0;
-      }
-    }
+    ({ prioritized, deprioritized } = transactionUtils.identifyPrioritizedTransactions(transactions, 'effectiveFeePerVsize'));
 
     // transactions missing from near the end of our template are probably not being censored
     let overflowWeightRemaining = overflowWeight - (config.MEMPOOL.BLOCK_WEIGHT_UNITS - totalWeight);

backend/src/api/bitcoin/bitcoin-api.ts

@@ -323,6 +323,7 @@ class BitcoinApi implements AbstractBitcoinApi {
       'witness_v1_taproot': 'v1_p2tr',
       'nonstandard': 'nonstandard',
       'multisig': 'multisig',
+      'anchor': 'anchor',
       'nulldata': 'op_return'
     };
 

backend/src/api/blocks.ts

@@ -219,10 +219,10 @@ class Blocks {
     };
   }
 
-  public summarizeBlockTransactions(hash: string, transactions: TransactionExtended[]): BlockSummary {
+  public summarizeBlockTransactions(hash: string, height: number, transactions: TransactionExtended[]): BlockSummary {
     return {
       id: hash,
-      transactions: Common.classifyTransactions(transactions),
+      transactions: Common.classifyTransactions(transactions, height),
     };
   }
 
@@ -616,7 +616,7 @@ class Blocks {
           // add CPFP
           const cpfpSummary = calculateGoodBlockCpfp(height, txs, []);
           // classify
-          const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, cpfpSummary.transactions);
+          const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, height, cpfpSummary.transactions);
           await BlocksSummariesRepository.$saveTransactions(height, blockHash, classifiedTxs, 2);
           if (unclassifiedBlocks[height].version < 2 && targetSummaryVersion === 2) {
             const cpfpClusters = await CpfpRepository.$getClustersAt(height);
@@ -653,7 +653,7 @@ class Blocks {
             }
             const cpfpSummary = calculateGoodBlockCpfp(height, templateTxs?.filter(tx => tx['effectiveFeePerVsize'] != null) as MempoolTransactionExtended[], []);
             // classify
-            const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, cpfpSummary.transactions);
+            const { transactions: classifiedTxs } = this.summarizeBlockTransactions(blockHash, height, cpfpSummary.transactions);
             const classifiedTxMap: { [txid: string]: TransactionClassified } = {};
             for (const tx of classifiedTxs) {
               classifiedTxMap[tx.txid] = tx;
@@ -912,7 +912,7 @@ class Blocks {
       }
       const cpfpSummary: CpfpSummary = calculateGoodBlockCpfp(block.height, transactions, accelerations.map(a => ({ txid: a.txid, max_bid: a.feeDelta })));
       const blockExtended: BlockExtended = await this.$getBlockExtended(block, cpfpSummary.transactions);
-      const blockSummary: BlockSummary = this.summarizeBlockTransactions(block.id, cpfpSummary.transactions);
+      const blockSummary: BlockSummary = this.summarizeBlockTransactions(block.id, block.height, cpfpSummary.transactions);
       this.updateTimerProgress(timer, `got block data for ${this.currentBlockHeight}`);
 
       if (Common.indexingEnabled()) {
@@ -1169,7 +1169,7 @@ class Blocks {
         transactions: cpfpSummary.transactions.map(tx => {
           let flags: number = 0;
           try {
-            flags = Common.getTransactionFlags(tx);
+            flags = Common.getTransactionFlags(tx, height);
           } catch (e) {
             logger.warn('Failed to classify transaction: ' + (e instanceof Error ? e.message : e));
           }
@@ -1188,7 +1188,7 @@ class Blocks {
     } else {
       if (config.MEMPOOL.BACKEND === 'esplora') {
         const txs = (await bitcoinApi.$getTxsForBlock(hash)).map(tx => transactionUtils.extendTransaction(tx));
-        summary = this.summarizeBlockTransactions(hash, txs);
+        summary = this.summarizeBlockTransactions(hash, height || 0, txs);
         summaryVersion = 1;
       } else {
         // Call Core RPC
@@ -1324,7 +1324,7 @@ class Blocks {
           let summaryVersion = 0;
           if (config.MEMPOOL.BACKEND === 'esplora') {
             const txs = (await bitcoinApi.$getTxsForBlock(cleanBlock.hash)).map(tx => transactionUtils.extendTransaction(tx));
-            summary = this.summarizeBlockTransactions(cleanBlock.hash, txs);
+            summary = this.summarizeBlockTransactions(cleanBlock.hash, cleanBlock.height, txs);
             summaryVersion = 1;
           } else {
             // Call Core RPC

backend/src/api/common.ts

@@ -10,7 +10,6 @@ import logger from '../logger';
 import { getVarIntLength, opcodes, parseMultisigScript } from '../utils/bitcoin-script';
 
 // Bitcoin Core default policy settings
-const TX_MAX_STANDARD_VERSION = 2;
 const MAX_STANDARD_TX_WEIGHT = 400_000;
 const MAX_BLOCK_SIGOPS_COST = 80_000;
 const MAX_STANDARD_TX_SIGOPS_COST = (MAX_BLOCK_SIGOPS_COST / 5);
@@ -200,10 +199,13 @@ export class Common {
    *
    * returns true early if any standardness rule is violated, otherwise false
    * (except for non-mandatory-script-verify-flag and p2sh script evaluation rules which are *not* enforced)
+   *
+   * As standardness rules change, we'll need to apply the rules in force *at the time* to older blocks.
+   * For now, just pull out individual rules into versioned functions where necessary.
    */
-  static isNonStandard(tx: TransactionExtended): boolean {
+  static isNonStandard(tx: TransactionExtended, height?: number): boolean {
     // version
-    if (tx.version > TX_MAX_STANDARD_VERSION) {
+    if (this.isNonStandardVersion(tx, height)) {
       return true;
     }
 
@@ -250,6 +252,8 @@ export class Common {
         }
       } else if (['unknown', 'provably_unspendable', 'empty'].includes(vin.prevout?.scriptpubkey_type || '')) {
         return true;
+      } else if (this.isNonStandardAnchor(tx, height)) {
+        return true;
       }
       // TODO: bad-witness-nonstandard
     }
@@ -335,6 +339,49 @@ export class Common {
     return false;
   }
 
+  // Individual versioned standardness rules
+
+  static V3_STANDARDNESS_ACTIVATION_HEIGHT = {
+    'testnet4': 42_000,
+    'testnet': 2_900_000,
+    'signet': 211_000,
+    '': 863_500,
+  };
+  static isNonStandardVersion(tx: TransactionExtended, height?: number): boolean {
+    let TX_MAX_STANDARD_VERSION = 3;
+    if (
+      height != null
+      && this.V3_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+      && height <= this.V3_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+    ) {
+      // V3 transactions were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+      TX_MAX_STANDARD_VERSION = 2;
+    }
+
+    if (tx.version > TX_MAX_STANDARD_VERSION) {
+      return true;
+    }
+    return false;
+  }
+
+  static ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT = {
+    'testnet4': 42_000,
+    'testnet': 2_900_000,
+    'signet': 211_000,
+    '': 863_500,
+  };
+  static isNonStandardAnchor(tx: TransactionExtended, height?: number): boolean {
+    if (
+      height != null
+      && this.ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+      && height <= this.ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[config.MEMPOOL.NETWORK]
+    ) {
+      // anchor outputs were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+      return true;
+    }
+    return false;
+  }
+
   static getNonWitnessSize(tx: TransactionExtended): number {
     let weight = tx.weight;
     let hasWitness = false;
@@ -415,7 +462,7 @@ export class Common {
     return flags;
   }
 
-  static getTransactionFlags(tx: TransactionExtended): number {
+  static getTransactionFlags(tx: TransactionExtended, height?: number): number {
     let flags = tx.flags ? BigInt(tx.flags) : 0n;
 
     // Update variable flags (CPFP, RBF)
@@ -548,7 +595,7 @@ export class Common {
     if (hasFakePubkey) {
       flags |= TransactionFlags.fake_pubkey;
     }
-    
+
     // fast but bad heuristic to detect possible coinjoins
     // (at least 5 inputs and 5 outputs, less than half of which are unique amounts, with no address reuse)
     const addressReuse = Object.keys(reusedOutputAddresses).reduce((acc, key) => Math.max(acc, (reusedInputAddresses[key] || 0) + (reusedOutputAddresses[key] || 0)), 0) > 1;
@@ -564,17 +611,17 @@ export class Common {
       flags |= TransactionFlags.batch_payout;
     }
 
-    if (this.isNonStandard(tx)) {
+    if (this.isNonStandard(tx, height)) {
       flags |= TransactionFlags.nonstandard;
     }
 
     return Number(flags);
   }
 
-  static classifyTransaction(tx: TransactionExtended): TransactionClassified {
+  static classifyTransaction(tx: TransactionExtended, height?: number): TransactionClassified {
     let flags = 0;
     try {
-      flags = Common.getTransactionFlags(tx);
+      flags = Common.getTransactionFlags(tx, height);
     } catch (e) {
       logger.warn('Failed to add classification flags to transaction: ' + (e instanceof Error ? e.message : e));
     }
@@ -585,8 +632,8 @@ export class Common {
     };
   }
 
-  static classifyTransactions(txs: TransactionExtended[]): TransactionClassified[] {
-    return txs.map(Common.classifyTransaction);
+  static classifyTransactions(txs: TransactionExtended[], height?: number): TransactionClassified[] {
+    return txs.map(tx => Common.classifyTransaction(tx, height));
   }
 
   static stripTransaction(tx: TransactionExtended): TransactionStripped {

backend/src/api/database-migration.ts

@@ -7,7 +7,7 @@ import cpfpRepository from '../repositories/CpfpRepository';
 import { RowDataPacket } from 'mysql2';
 
 class DatabaseMigration {
-  private static currentVersion = 81;
+  private static currentVersion = 82;
   private queryTimeout = 3600_000;
   private statisticsAddedIndexed = false;
   private uniqueLogs: string[] = [];
@@ -700,6 +700,11 @@ class DatabaseMigration {
       await this.$executeQuery('ALTER TABLE `blocks_audits` ADD unseen_txs JSON DEFAULT "[]"');
       await this.updateToSchemaVersion(81);
     }
+
+    if (databaseSchemaVersion < 82 && isBitcoin === true && config.MEMPOOL.NETWORK === 'mainnet') {
+      await this.$fixBadV1AuditBlocks();
+      await this.updateToSchemaVersion(82);
+    }
   }
 
   /**
@@ -1314,6 +1319,28 @@ class DatabaseMigration {
       logger.warn(`Failed to migrate cpfp transaction data`);
     }
   }
+
+  private async $fixBadV1AuditBlocks(): Promise<void> {
+    const badBlocks = [
+      '000000000000000000011ad49227fc8c9ba0ca96ad2ebce41a862f9a244478dc',
+      '000000000000000000010ac1f68b3080153f2826ffddc87ceffdd68ed97d6960',
+      '000000000000000000024cbdafeb2660ae8bd2947d166e7fe15d1689e86b2cf7',
+      '00000000000000000002e1dbfbf6ae057f331992a058b822644b368034f87286',
+      '0000000000000000000019973b2778f08ad6d21e083302ff0833d17066921ebb',
+    ];
+
+    for (const hash of badBlocks) {
+      try {
+        await this.$executeQuery(`
+          UPDATE blocks_audits
+          SET prioritized_txs = '[]'
+          WHERE hash = '${hash}'
+        `, true);
+      } catch (e) {
+        continue;
+      }
+    }
+  }
 }
 
 export default new DatabaseMigration();

backend/src/api/mining/mining-routes.ts

@@ -30,6 +30,7 @@ class MiningRoutes {
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/fee-rates/:interval', this.$getHistoricalBlockFeeRates)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/sizes-weights/:interval', this.$getHistoricalBlockSizeAndWeight)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/difficulty-adjustments/:interval', this.$getDifficultyAdjustments)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'mining/difficulty-adjustment/:height', this.$getDifficultyAdjustment)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/predictions/:interval', this.$getHistoricalBlocksHealth)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/audit/scores', this.$getBlockAuditScores)
       .get(config.MEMPOOL.API_URL_PREFIX + 'mining/blocks/audit/scores/:height', this.$getBlockAuditScores)
@@ -297,6 +298,18 @@ class MiningRoutes {
     }
   }
 
+  private async $getDifficultyAdjustment(req: Request, res: Response) {
+    try {
+      const adjustment = await DifficultyAdjustmentsRepository.$getAdjustmentAtHeight(parseInt(req.params.height, 10));
+      res.header('Pragma', 'public');
+      res.header('Cache-control', 'public');
+      res.setHeader('Expires', new Date(Date.now() + 1000 * 300).toUTCString());
+      res.json(adjustment);
+    } catch (e) {
+      res.status(e instanceof Error && e.message === 'not found' ? 204 : 500).send(e instanceof Error ? e.message : e);
+    }
+  }
+
   private async $getRewardStats(req: Request, res: Response) {
     try {
       const response = await mining.$getRewardStats(parseInt(req.params.blockCount, 10));

backend/src/api/transaction-utils.ts

@@ -338,6 +338,87 @@ class TransactionUtils {
     const positionOfScript = hasAnnex ? witness.length - 3 : witness.length - 2;
     return witness[positionOfScript];
   }
+
+  // calculate the most parsimonious set of prioritizations given a list of block transactions
+  // (i.e. the most likely prioritizations and deprioritizations)
+  public identifyPrioritizedTransactions(transactions: any[], rateKey: string): { prioritized: string[], deprioritized: string[] } {
+    // find the longest increasing subsequence of transactions
+    // (adapted from https://en.wikipedia.org/wiki/Longest_increasing_subsequence#Efficient_algorithms)
+    // should be O(n log n)
+    const X = transactions.slice(1).reverse().map((tx) => ({ txid: tx.txid, rate: tx[rateKey] })); // standard block order is by *decreasing* effective fee rate, but we want to iterate in increasing order (and skip the coinbase)
+    if (X.length < 2) {
+      return { prioritized: [], deprioritized: [] };
+    }
+    const N = X.length;
+    const P: number[] = new Array(N);
+    const M: number[] = new Array(N + 1);
+    M[0] = -1; // undefined so can be set to any value
+
+    let L = 0;
+    for (let i = 0; i < N; i++) {
+      // Binary search for the smallest positive l ≤ L
+      // such that X[M[l]].effectiveFeePerVsize > X[i].effectiveFeePerVsize
+      let lo = 1;
+      let hi = L + 1;
+      while (lo < hi) {
+        const mid = lo + Math.floor((hi - lo) / 2); // lo <= mid < hi
+        if (X[M[mid]].rate > X[i].rate) {
+          hi = mid;
+        } else { // if X[M[mid]].effectiveFeePerVsize < X[i].effectiveFeePerVsize
+          lo = mid + 1;
+        }
+      }
+
+      // After searching, lo == hi is 1 greater than the
+      // length of the longest prefix of X[i]
+      const newL = lo;
+
+      // The predecessor of X[i] is the last index of
+      // the subsequence of length newL-1
+      P[i] = M[newL - 1];
+      M[newL] = i;
+
+      if (newL > L) {
+        // If we found a subsequence longer than any we've
+        // found yet, update L
+        L = newL;
+      }
+    }
+
+    // Reconstruct the longest increasing subsequence
+    // It consists of the values of X at the L indices:
+    // ..., P[P[M[L]]], P[M[L]], M[L]
+    const LIS: any[] = new Array(L);
+    let k = M[L];
+    for (let j = L - 1; j >= 0; j--) {
+      LIS[j] = X[k];
+      k = P[k];
+    }
+
+    const lisMap = new Map<string, number>();
+    LIS.forEach((tx, index) => lisMap.set(tx.txid, index));
+
+    const prioritized: string[] = [];
+    const deprioritized: string[] = [];
+
+    let lastRate = X[0].rate;
+
+    for (const tx of X) {
+      if (lisMap.has(tx.txid)) {
+        lastRate = tx.rate;
+      } else {
+        if (Math.abs(tx.rate - lastRate) < 0.1) {
+          // skip if the rate is almost the same as the previous transaction
+        } else if (tx.rate <= lastRate) {
+          prioritized.push(tx.txid);
+        } else {
+          deprioritized.push(tx.txid);
+        }
+      }
+    }
+
+    return { prioritized, deprioritized };
+  }
 }
 
 export default new TransactionUtils();

backend/src/repositories/BlocksRepository.ts

@@ -1106,7 +1106,7 @@ class BlocksRepository {
         let summaryVersion = 0;
         if (config.MEMPOOL.BACKEND === 'esplora') {
           const txs = (await bitcoinApi.$getTxsForBlock(dbBlk.id)).map(tx => transactionUtils.extendTransaction(tx));
-          summary = blocks.summarizeBlockTransactions(dbBlk.id, txs);
+          summary = blocks.summarizeBlockTransactions(dbBlk.id, dbBlk.height, txs);
           summaryVersion = 1;
         } else {
           // Call Core RPC

backend/src/repositories/DifficultyAdjustmentsRepository.ts

@@ -88,6 +88,22 @@ class DifficultyAdjustmentsRepository {
     }
   }
 
+  public async $getAdjustmentAtHeight(height: number): Promise<IndexedDifficultyAdjustment> {
+    try {
+      if (isNaN(height)) {
+        throw new Error(`argument must be a number`);
+      }
+      const [rows] = await DB.query(`SELECT * FROM difficulty_adjustments WHERE height = ?`, [height]);
+      if (!rows[0]) {
+        throw new Error(`not found`);
+      }
+      return rows[0] as IndexedDifficultyAdjustment;
+    } catch (e: any) {
+      logger.err(`Cannot get difficulty adjustment from the database. Reason: ${e instanceof Error ? e.message : e}`, logger.tags.mining);
+      throw e;
+    }
+  }
+
   public async $getAdjustmentsHeights(): Promise<number[]> {
     try {
       const [rows]: any[] = await DB.query(`SELECT height FROM difficulty_adjustments`);

backend/src/utils/bitcoin-script.ts

@@ -158,7 +158,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
   if (!opN) {
     return;
   }
-  if (!opN.startsWith('OP_PUSHNUM_')) {
+  if (opN !== 'OP_0' && !opN.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const n = parseInt(opN.match(/[0-9]+/)?.[0] || '', 10);
@@ -178,7 +178,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
   if (!opM) {
     return;
   }
-  if (!opM.startsWith('OP_PUSHNUM_')) {
+  if (opM !== 'OP_0' && !opM.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const m = parseInt(opM.match(/[0-9]+/)?.[0] || '', 10);

frontend/README.md

@@ -33,7 +33,7 @@ $ npm run config:defaults:liquid
 
 ### 3. Run the Frontend
 
-_Make sure to use Node.js 16.10 and npm 7._
+_Make sure to use Node.js 20.x and npm 9.x or newer._
 
 Install project dependencies and run the frontend server:
 
@@ -70,7 +70,7 @@ Set up the [Mempool backend](../backend/) first, if you haven't already.
 
 ### 1. Build the Frontend
 
-_Make sure to use Node.js 16.10 and npm 7._
+_Make sure to use Node.js 20.x and npm 9.x or newer._
 
 Build the frontend:
 

frontend/cypress/fixtures/mainnet_mempoolInfo.json

@@ -750,7 +750,7 @@
     },
     "backendInfo": {
       "hostname": "node205.tk7.mempool.space",
-      "version": "3.0.0",
+      "version": "3.1.0-dev",
       "gitCommit": "abbc8a134",
       "lightning": false
     },

frontend/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "mempool-frontend",
-  "version": "3.0.0",
+  "version": "3.1.0-dev",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "mempool-frontend",
-      "version": "3.0.0",
+      "version": "3.1.0-dev",
       "license": "GNU Affero General Public License v3.0",
       "dependencies": {
         "@angular-devkit/build-angular": "^17.3.1",
@@ -32,6 +32,7 @@
         "bootstrap": "~4.6.2",
         "browserify": "^17.0.0",
         "clipboard": "^2.0.11",
+        "cypress": "^13.14.0",
         "domino": "^2.1.6",
         "echarts": "~5.5.0",
         "esbuild": "^0.23.0",
@@ -42,7 +43,7 @@
         "rxjs": "~7.8.1",
         "tinyify": "^4.0.0",
         "tlite": "^0.1.9",
-        "tslib": "~2.6.0",
+        "tslib": "~2.7.0",
         "zone.js": "~0.14.4"
       },
       "devDependencies": {
@@ -62,7 +63,7 @@
       "optionalDependencies": {
         "@cypress/schematic": "^2.5.0",
         "@types/cypress": "^1.1.3",
-        "cypress": "^13.13.0",
+        "cypress": "^13.14.0",
         "cypress-fail-on-console-error": "~5.1.0",
         "cypress-wait-until": "^2.0.1",
         "mock-socket": "~9.3.1",
@@ -699,6 +700,11 @@
         "node": ">=10"
       }
     },
+    "node_modules/@angular-devkit/build-angular/node_modules/tslib": {
+      "version": "2.6.2",
+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.6.2.tgz",
+      "integrity": "sha512-AEYxH93jGFPn/a2iVAwW87VuUIkR1FVUKB77NwMF7nBTDkDrrT/Hpt/IrCJ0QXhW27jTBDcf5ZY7w6RiqTMw2Q=="
+    },
     "node_modules/@angular-devkit/build-webpack": {
       "version": "0.1703.1",
       "resolved": "https://registry.npmjs.org/@angular-devkit/build-webpack/-/build-webpack-0.1703.1.tgz",
@@ -8040,13 +8046,13 @@
       "peer": true
     },
     "node_modules/cypress": {
-      "version": "13.13.0",
-      "resolved": "https://registry.npmjs.org/cypress/-/cypress-13.13.0.tgz",
-      "integrity": "sha512-ou/MQUDq4tcDJI2FsPaod2FZpex4kpIK43JJlcBgWrX8WX7R/05ZxGTuxedOuZBfxjZxja+fbijZGyxiLP6CFA==",
+      "version": "13.14.0",
+      "resolved": "https://registry.npmjs.org/cypress/-/cypress-13.14.0.tgz",
+      "integrity": "sha512-r0+nhd033x883YL6068futewUsl02Q7rWiinyAAIBDW/OOTn+UMILWgNuCiY3vtJjd53efOqq5R9dctQk/rKiw==",
       "hasInstallScript": true,
       "optional": true,
       "dependencies": {
-        "@cypress/request": "^3.0.0",
+        "@cypress/request": "^3.0.1",
         "@cypress/xvfb": "^1.2.4",
         "@types/sinonjs__fake-timers": "8.1.1",
         "@types/sizzle": "^2.3.2",
@@ -8805,9 +8811,9 @@
       "integrity": "sha512-XzWNH4ZSa9BwVUQSDorPWAUQ5WGuYz7zJUNpNif40zFCiCl20t8zgylmreNmn26h5kiyw2lg7RfTmeMBsDklqg=="
     },
     "node_modules/elliptic": {
-      "version": "6.5.4",
-      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.5.4.tgz",
-      "integrity": "sha512-iLhC6ULemrljPZb+QutR5TQGB+pdW6KGD5RSegS+8sorOZT+rdQFbsQFJgvN3eRqNALqJer4oQ16YvJHlU8hzQ==",
+      "version": "6.5.7",
+      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.5.7.tgz",
+      "integrity": "sha512-ESVCtTwiA+XhY3wyh24QqRGBoP3rEdDUl3EDUUo9tft074fi19IrdpH7hLCMMP3CIj7jb3W96rn8lt/BqIlt5Q==",
       "dependencies": {
         "bn.js": "^4.11.9",
         "brorand": "^1.1.0",
@@ -16925,9 +16931,9 @@
       }
     },
     "node_modules/tslib": {
-      "version": "2.6.2",
-      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.6.2.tgz",
-      "integrity": "sha512-AEYxH93jGFPn/a2iVAwW87VuUIkR1FVUKB77NwMF7nBTDkDrrT/Hpt/IrCJ0QXhW27jTBDcf5ZY7w6RiqTMw2Q=="
+      "version": "2.7.0",
+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.7.0.tgz",
+      "integrity": "sha512-gLXCKdN1/j47AiHiOkJN69hJmcbGTHI0ImLmbYLHykhgeN0jVGola9yVjFgzCUklsZQMW55o+dW7IXv3RCXDzA=="
     },
     "node_modules/tuf-js": {
       "version": "2.2.0",
@@ -18849,6 +18855,11 @@
           "requires": {
             "lru-cache": "^6.0.0"
           }
+        },
+        "tslib": {
+          "version": "2.6.2",
+          "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.6.2.tgz",
+          "integrity": "sha512-AEYxH93jGFPn/a2iVAwW87VuUIkR1FVUKB77NwMF7nBTDkDrrT/Hpt/IrCJ0QXhW27jTBDcf5ZY7w6RiqTMw2Q=="
         }
       }
     },
@@ -24127,12 +24138,12 @@
       "peer": true
     },
     "cypress": {
-      "version": "13.13.0",
-      "resolved": "https://registry.npmjs.org/cypress/-/cypress-13.13.0.tgz",
-      "integrity": "sha512-ou/MQUDq4tcDJI2FsPaod2FZpex4kpIK43JJlcBgWrX8WX7R/05ZxGTuxedOuZBfxjZxja+fbijZGyxiLP6CFA==",
+      "version": "13.14.0",
+      "resolved": "https://registry.npmjs.org/cypress/-/cypress-13.14.0.tgz",
+      "integrity": "sha512-r0+nhd033x883YL6068futewUsl02Q7rWiinyAAIBDW/OOTn+UMILWgNuCiY3vtJjd53efOqq5R9dctQk/rKiw==",
       "optional": true,
       "requires": {
-        "@cypress/request": "^3.0.0",
+        "@cypress/request": "^3.0.1",
         "@cypress/xvfb": "^1.2.4",
         "@types/sinonjs__fake-timers": "8.1.1",
         "@types/sizzle": "^2.3.2",
@@ -24723,9 +24734,9 @@
       "integrity": "sha512-XzWNH4ZSa9BwVUQSDorPWAUQ5WGuYz7zJUNpNif40zFCiCl20t8zgylmreNmn26h5kiyw2lg7RfTmeMBsDklqg=="
     },
     "elliptic": {
-      "version": "6.5.4",
-      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.5.4.tgz",
-      "integrity": "sha512-iLhC6ULemrljPZb+QutR5TQGB+pdW6KGD5RSegS+8sorOZT+rdQFbsQFJgvN3eRqNALqJer4oQ16YvJHlU8hzQ==",
+      "version": "6.5.7",
+      "resolved": "https://registry.npmjs.org/elliptic/-/elliptic-6.5.7.tgz",
+      "integrity": "sha512-ESVCtTwiA+XhY3wyh24QqRGBoP3rEdDUl3EDUUo9tft074fi19IrdpH7hLCMMP3CIj7jb3W96rn8lt/BqIlt5Q==",
       "requires": {
         "bn.js": "^4.11.9",
         "brorand": "^1.1.0",
@@ -30763,9 +30774,9 @@
       }
     },
     "tslib": {
-      "version": "2.6.2",
-      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.6.2.tgz",
-      "integrity": "sha512-AEYxH93jGFPn/a2iVAwW87VuUIkR1FVUKB77NwMF7nBTDkDrrT/Hpt/IrCJ0QXhW27jTBDcf5ZY7w6RiqTMw2Q=="
+      "version": "2.7.0",
+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.7.0.tgz",
+      "integrity": "sha512-gLXCKdN1/j47AiHiOkJN69hJmcbGTHI0ImLmbYLHykhgeN0jVGola9yVjFgzCUklsZQMW55o+dW7IXv3RCXDzA=="
     },
     "tuf-js": {
       "version": "2.2.0",

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mempool-frontend",
-  "version": "3.0.0",
+  "version": "3.1.0-dev",
   "description": "Bitcoin mempool visualizer and blockchain explorer backend",
   "license": "GNU Affero General Public License v3.0",
   "homepage": "https://mempool.space",
@@ -95,7 +95,7 @@
     "esbuild": "^0.23.0",
     "tinyify": "^4.0.0",
     "tlite": "^0.1.9",
-    "tslib": "~2.6.0",
+    "tslib": "~2.7.0",
     "zone.js": "~0.14.4"
   },
   "devDependencies": {
@@ -115,7 +115,7 @@
   "optionalDependencies": {
     "@cypress/schematic": "^2.5.0",
     "@types/cypress": "^1.1.3",
-    "cypress": "^13.13.0",
+    "cypress": "^13.14.0",
     "cypress-fail-on-console-error": "~5.1.0",
     "cypress-wait-until": "^2.0.1",
     "mock-socket": "~9.3.1",

frontend/src/app/bitcoin.utils.ts

@@ -135,7 +135,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
     return;
   }
   const opN = ops.pop();
-  if (!opN.startsWith('OP_PUSHNUM_')) {
+  if (opN !== 'OP_0' && !opN.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const n = parseInt(opN.match(/[0-9]+/)[0], 10);
@@ -152,7 +152,7 @@ export function parseMultisigScript(script: string): void | { m: number, n: numb
     }
   }
   const opM = ops.pop();
-  if (!opM.startsWith('OP_PUSHNUM_')) {
+  if (opM !== 'OP_0' && !opM.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const m = parseInt(opM.match(/[0-9]+/)[0], 10);

frontend/src/app/components/address-labels/address-labels.component.ts

@@ -55,7 +55,7 @@ export class AddressLabelsComponent implements OnChanges {
   }
 
   handleVin() {
-    const address = new AddressTypeInfo(this.network || 'mainnet', this.vin.prevout?.scriptpubkey_address, this.vin.prevout?.scriptpubkey_type as AddressType, [this.vin])
+    const address = new AddressTypeInfo(this.network || 'mainnet', this.vin.prevout?.scriptpubkey_address, this.vin.prevout?.scriptpubkey_type as AddressType, [this.vin]);
     if (address?.scripts.size) {
       const script = address?.scripts.values().next().value;
       if (script.template?.label) {

frontend/src/app/components/block-overview-graph/block-overview-graph.component.ts

@@ -198,7 +198,7 @@ export class BlockOverviewGraphComponent implements AfterViewInit, OnDestroy, On
   }
 
   // initialize the scene without any entry transition
-  setup(transactions: TransactionStripped[]): void {
+  setup(transactions: TransactionStripped[], sort: boolean = false): void {
     const filtersAvailable = transactions.reduce((flagSet, tx) => flagSet || tx.flags > 0, false);
     if (filtersAvailable !== this.filtersAvailable) {
       this.setFilterFlags();
@@ -206,7 +206,7 @@ export class BlockOverviewGraphComponent implements AfterViewInit, OnDestroy, On
     this.filtersAvailable = filtersAvailable;
     if (this.scene) {
       this.clearUpdateQueue();
-      this.scene.setup(transactions);
+      this.scene.setup(transactions, sort);
       this.readyNextFrame = true;
       this.start();
       this.updateSearchHighlight();

frontend/src/app/components/block-overview-graph/block-scene.ts

@@ -88,16 +88,19 @@ export default class BlockScene {
   }
 
   // set up the scene with an initial set of transactions, without any transition animation
-  setup(txs: TransactionStripped[]) {
+  setup(txs: TransactionStripped[], sort: boolean = false) {
     // clean up any old transactions
     Object.values(this.txs).forEach(tx => {
       tx.destroy();
       delete this.txs[tx.txid];
     });
     this.layout = new BlockLayout({ width: this.gridWidth, height: this.gridHeight });
-    txs.forEach(tx => {
-      const txView = new TxView(tx, this);
-      this.txs[tx.txid] = txView;
+    let txViews = txs.map(tx => new TxView(tx, this));
+    if (sort) {
+      txViews = txViews.sort(feeRateDescending);
+    }
+    txViews.forEach(txView => {
+      this.txs[txView.txid] = txView;
       this.place(txView);
       this.saveGridToScreenPosition(txView);
       this.applyTxUpdate(txView, {

frontend/src/app/components/block-overview-graph/tx-view.ts

@@ -33,7 +33,7 @@ export default class TxView implements TransactionStripped {
   flags: number;
   bigintFlags?: bigint | null = 0b00000100_00000000_00000000_00000000n;
   time?: number;
-  status?: 'found' | 'missing' | 'sigop' | 'fresh' | 'freshcpfp' | 'added' | 'added_prioritized' | 'prioritized' | 'censored' | 'selected' | 'rbf' | 'accelerated';
+  status?: 'found' | 'missing' | 'sigop' | 'fresh' | 'freshcpfp' | 'added' | 'added_prioritized' | 'prioritized' | 'added_deprioritized' | 'deprioritized' | 'censored' | 'selected' | 'rbf' | 'accelerated';
   context?: 'projected' | 'actual';
   scene?: BlockScene;
 

frontend/src/app/components/block-overview-graph/utils.ts

@@ -142,6 +142,10 @@ export function defaultColorFunction(
       return auditColors.added_prioritized;
     case 'prioritized':
       return auditColors.prioritized;
+    case 'added_deprioritized':
+      return auditColors.added_prioritized;
+    case 'deprioritized':
+      return auditColors.prioritized;
     case 'selected':
       return colors.marginal[levelIndex] || colors.marginal[defaultMempoolFeeColors.length - 1];
     case 'accelerated':

frontend/src/app/components/block-overview-tooltip/block-overview-tooltip.component.html

@@ -79,6 +79,11 @@
               <span class="badge badge-warning" i18n="tx-features.tag.added|Added">Added</span>
               <span class="badge badge-warning ml-1" i18n="tx-features.tag.prioritized|Prioritized">Prioritized</span>
             </ng-container>
+            <span *ngSwitchCase="'deprioritized'" class="badge badge-warning" i18n="tx-features.tag.prioritized|Deprioritized">Deprioritized</span>
+            <ng-container *ngSwitchCase="'added_deprioritized'">
+              <span class="badge badge-warning" i18n="tx-features.tag.added|Added">Added</span>
+              <span class="badge badge-warning ml-1" i18n="tx-features.tag.prioritized|Deprioritized">Deprioritized</span>
+            </ng-container>
             <span *ngSwitchCase="'selected'" class="badge badge-warning" i18n="transaction.audit.marginal">Marginal fee rate</span>
             <span *ngSwitchCase="'rbf'" class="badge badge-warning" i18n="tx-features.tag.conflict|Conflict">Conflict</span>
             <span *ngSwitchCase="'accelerated'" class="badge badge-accelerated" i18n="transaction.audit.accelerated">Accelerated</span>

frontend/src/app/components/block/block.component.html

@@ -78,6 +78,25 @@
                   </ng-template>
                 </td>
               </tr>
+              <tr *ngIf="this.stateService.network === '' && block.height % 2016 === 0">
+                <td i18n="mining.difficulty-adjustment">Adjustment</td>
+                <td>
+                  <ng-container *ngIf="cacheService.daCache[block.height]?.adjustment > 0; else loadingAdjustment">
+                    <div [style.color]="cacheService.daCache[block.height].adjustment > 1 ? 'var(--green)' : (cacheService.daCache[block.height].adjustment < 1 ? 'var(--red)' : '')">
+                      @if (cacheService.daCache[block.height].adjustment > 1) {
+                        <fa-icon class="retarget-sign up" [icon]="['fas', 'caret-up']" [fixedWidth]="true"></fa-icon>
+                      } @else if (cacheService.daCache[block.height].adjustment < 1) {
+                        <fa-icon class="retarget-sign" [icon]="['fas', 'caret-down']" [fixedWidth]="true"></fa-icon>
+                      }
+                      {{ (cacheService.daCache[block.height].adjustment - 1) * 100 | absolute | number: '1.2-2' }}
+                      <span class="symbol">%</span>
+                    </div>
+                  </ng-container>
+                  <ng-template #loadingAdjustment>
+                    <span class="skeleton-loader" style="max-width: 60px"></span>
+                  </ng-template>
+                </td>
+              </tr>
             </ng-container>
             <ng-template #skeletonRows>
               <tr>
@@ -193,6 +212,10 @@
         </span>
         </td>
       </tr>
+      <tr *ngIf="this.stateService.network === '' && block.height % 2016 === 0">
+        <td i18n="block.difficulty">Difficulty</td>
+        <td>{{ block.difficulty | amountShortener: 2 }}</td>
+      </tr>
     </ng-container>
     <ng-template #loadingRest>
       <tr>

frontend/src/app/components/block/block.component.scss

@@ -280,3 +280,11 @@ h1 {
   top: -1px;
   margin-right: 2px;
 }
+
+.retarget-sign {
+  margin-right: -3px;
+  &.up {
+    position: relative;
+    top: 2px;
+  }
+}

frontend/src/app/components/block/block.component.ts

@@ -17,6 +17,7 @@ import { PriceService, Price } from '../../services/price.service';
 import { CacheService } from '../../services/cache.service';
 import { ServicesApiServices } from '../../services/services-api.service';
 import { PreloadService } from '../../services/preload.service';
+import { identifyPrioritizedTransactions } from '../../shared/transaction.utils';
 
 @Component({
   selector: 'app-block',
@@ -98,7 +99,7 @@ export class BlockComponent implements OnInit, OnDestroy {
     private relativeUrlPipe: RelativeUrlPipe,
     private apiService: ApiService,
     private priceService: PriceService,
-    private cacheService: CacheService,
+    public cacheService: CacheService,
     private servicesApiService: ServicesApiServices,
     private cd: ChangeDetectorRef,
     private preloadService: PreloadService,
@@ -524,6 +525,7 @@ export class BlockComponent implements OnInit, OnDestroy {
       const isUnseen = {};
       const isAdded = {};
       const isPrioritized = {};
+      const isDeprioritized = {};
       const isCensored = {};
       const isMissing = {};
       const isSelected = {};
@@ -535,6 +537,17 @@ export class BlockComponent implements OnInit, OnDestroy {
       this.numUnexpected = 0;
 
       if (blockAudit?.template) {
+        // augment with locally calculated *de*prioritized transactions if possible
+        const { prioritized, deprioritized } = identifyPrioritizedTransactions(transactions);
+        // but if the local calculation produces returns unexpected results, don't use it
+        let useLocalDeprioritized = deprioritized.length < (transactions.length * 0.1);
+        for (const tx of prioritized) {
+          if (!isPrioritized[tx] && !isAccelerated[tx]) {
+            useLocalDeprioritized = false;
+            break;
+          }
+        }
+
         for (const tx of blockAudit.template) {
           inTemplate[tx.txid] = true;
           if (tx.acc) {
@@ -550,9 +563,14 @@ export class BlockComponent implements OnInit, OnDestroy {
         for (const txid of blockAudit.addedTxs) {
           isAdded[txid] = true;
         }
-        for (const txid of blockAudit.prioritizedTxs || []) {
+        for (const txid of blockAudit.prioritizedTxs) {
           isPrioritized[txid] = true;
         }
+        if (useLocalDeprioritized) {
+          for (const txid of deprioritized || []) {
+            isDeprioritized[txid] = true;
+          }
+        }
         for (const txid of blockAudit.missingTxs) {
           isCensored[txid] = true;
         }
@@ -608,6 +626,12 @@ export class BlockComponent implements OnInit, OnDestroy {
             } else {
               tx.status = 'prioritized';
             }
+          } else if (isDeprioritized[tx.txid]) {
+            if (isAdded[tx.txid] || (blockAudit.version > 0 && isUnseen[tx.txid])) {
+              tx.status = 'added_deprioritized';
+            } else {
+              tx.status = 'deprioritized';
+            }
           } else if (isAdded[tx.txid] && (blockAudit.version === 0 || isUnseen[tx.txid])) {
             tx.status = 'added';
           } else if (inTemplate[tx.txid]) {

frontend/src/app/components/blockchain-blocks/blockchain-blocks.component.ts

@@ -1,10 +1,12 @@
 import { Component, OnInit, OnDestroy, ChangeDetectionStrategy, ChangeDetectorRef, Input, OnChanges, SimpleChanges } from '@angular/core';
-import { Observable, Subscription, delay, filter, tap } from 'rxjs';
+import { Observable, Subscription, delay, filter, of, retryWhen, switchMap, take, tap, throwError } from 'rxjs';
 import { StateService } from '../../services/state.service';
 import { specialBlocks } from '../../app.constants';
 import { BlockExtended } from '../../interfaces/node-api.interface';
 import { Location } from '@angular/common';
 import { CacheService } from '../../services/cache.service';
+import { ApiService } from '../../services/api.service';
+import { colorFromRetarget } from '../../shared/common.utils';
 
 interface BlockchainBlock extends BlockExtended {
   placeholder?: boolean;
@@ -77,6 +79,7 @@ export class BlockchainBlocksComponent implements OnInit, OnChanges, OnDestroy {
   constructor(
     public stateService: StateService,
     public cacheService: CacheService,
+    public apiService: ApiService,
     private cd: ChangeDetectorRef,
     private location: Location,
   ) {
@@ -334,6 +337,31 @@ export class BlockchainBlocksComponent implements OnInit, OnChanges, OnDestroy {
     return this.specialBlocks[height]?.networks.includes(this.stateService.network || 'mainnet') ? true : false;
   }
 
+  isDA(height: number): boolean {
+    const isDA = height % 2016 === 0 && this.stateService.network === '';
+    if (isDA && !this.cacheService.daCache[height]?.exact) {
+      const estimatedAdjustment = this.cacheService.daCache[height]?.adjustment || 0;
+      this.cacheService.daCache[height] = { adjustment: estimatedAdjustment, exact: true };
+      this.apiService.getDifficultyAdjustmentByHeight$(height).pipe(
+        switchMap(da => {
+          const blocksAvailable = (this.height || this.chainTip) && this.blockStyles[(this.height || this.chainTip) - height];
+          return blocksAvailable ? of(da) : throwError(() => new Error());
+        }),
+        retryWhen(errors =>
+          errors.pipe(
+            delay(1000),
+            take(3)
+          )
+        ),
+        tap((da) => {
+          this.cacheService.daCache[height] = { adjustment: da?.adjustment || 1, exact: true };
+          this.blockStyles[(this.height || this.chainTip) - height].background = colorFromRetarget(da?.adjustment);
+        })
+      ).subscribe();
+    }
+    return isDA;
+  }
+
   getStyleForBlock(block: BlockchainBlock, index: number, animateEnterFrom: number = 0) {
     if (!block || block.placeholder) {
       return this.getStyleForPlaceholderBlock(index, animateEnterFrom);
@@ -349,7 +377,8 @@ export class BlockchainBlocksComponent implements OnInit, OnChanges, OnDestroy {
 
     return {
       left: addLeft + this.blockOffset * index + 'px',
-      background: `repeating-linear-gradient(
+      background: this.isDA(block.height) ? colorFromRetarget(this.cacheService.daCache[block.height]?.adjustment || 1) :
+      `repeating-linear-gradient(
         var(--secondary),
         var(--secondary) ${greenBackgroundHeight}%,
         ${this.gradientColors[this.network][0]} ${Math.max(greenBackgroundHeight, 0)}%,

frontend/src/app/components/difficulty-adjustments-table/difficulty-adjustments-table.components.ts

@@ -5,6 +5,7 @@ import { ApiService } from '../../services/api.service';
 import { formatNumber } from '@angular/common';
 import { selectPowerOfTen } from '../../bitcoin.utils';
 import { StateService } from '../../services/state.service';
+import { CacheService } from '../../services/cache.service';
 
 @Component({
   selector: 'app-difficulty-adjustments-table',
@@ -27,7 +28,8 @@ export class DifficultyAdjustmentsTable implements OnInit {
   constructor(
     @Inject(LOCALE_ID) public locale: string,
     private apiService: ApiService,
-    public stateService: StateService
+    public stateService: StateService,
+    private cacheService: CacheService,
   ) {
   }
 
@@ -52,6 +54,7 @@ export class DifficultyAdjustmentsTable implements OnInit {
                 adjustment[2] / selectedPowerOfTen.divider,
                 this.locale, `1.${decimals}-${decimals}`) + selectedPowerOfTen.unit
             });
+            this.cacheService.daCache[adjustment[1]] = { adjustment: adjustment[3], exact: true };
           }
           this.isLoading = false;
           return tableData.slice(0, 6);

frontend/src/app/components/mempool-block-overview/mempool-block-overview.component.ts

@@ -31,7 +31,7 @@ export class MempoolBlockOverviewComponent implements OnInit, OnDestroy, OnChang
 
   lastBlockHeight: number;
   blockIndex: number;
-  isLoading$ = new BehaviorSubject<boolean>(true);
+  isLoading$ = new BehaviorSubject<boolean>(false);
   timeLtrSubscription: Subscription;
   timeLtr: boolean;
   chainDirection: string = 'right';
@@ -95,6 +95,7 @@ export class MempoolBlockOverviewComponent implements OnInit, OnDestroy, OnChang
             }
           }
           this.updateBlock({
+            block: this.blockIndex,
             removed,
             changed,
             added
@@ -110,8 +111,11 @@ export class MempoolBlockOverviewComponent implements OnInit, OnDestroy, OnChang
       if (this.blockGraph) {
         this.blockGraph.clear(changes.index.currentValue > changes.index.previousValue ? this.chainDirection : this.poolDirection);
       }
-      this.isLoading$.next(true);
-      this.websocketService.startTrackMempoolBlock(changes.index.currentValue);
+      if (!this.websocketService.startTrackMempoolBlock(changes.index.currentValue) && this.stateService.mempoolBlockState && this.stateService.mempoolBlockState.block === changes.index.currentValue) {
+        this.resumeBlock(Object.values(this.stateService.mempoolBlockState.transactions));
+      } else {
+        this.isLoading$.next(true);
+      }
     }
   }
 
@@ -153,6 +157,19 @@ export class MempoolBlockOverviewComponent implements OnInit, OnDestroy, OnChang
     this.isLoading$.next(false);
   }
 
+  resumeBlock(transactionsStripped: TransactionStripped[]): void {
+    if (this.blockGraph) {
+      this.firstLoad = false;
+      this.blockGraph.setup(transactionsStripped, true);
+      this.blockIndex = this.index;
+      this.isLoading$.next(false);
+    } else {
+      requestAnimationFrame(() => {
+        this.resumeBlock(transactionsStripped);
+      });
+    }
+  }
+
   onTxClick(event: { tx: TransactionStripped, keyModifier: boolean }): void {
     const url = new RelativeUrlPipe(this.stateService).transform(`/tx/${event.tx.txid}`);
     if (!event.keyModifier) {

frontend/src/app/components/mempool-block/mempool-block.component.html

@@ -41,6 +41,25 @@
                 </div>
               </td>
             </tr>
+            <tr *ngIf="this.stateService.network === '' && mempoolBlock.height % 2016 === 0">
+              <td i18n="mining.difficulty-adjustment">Adjustment</td>
+              <td>
+                <ng-container *ngIf="cacheService.daCache[mempoolBlock.height]?.adjustment > 0; else loadingAdjustment">
+                  <div [style.color]="cacheService.daCache[mempoolBlock.height].adjustment > 1 ? 'var(--green)' : (cacheService.daCache[mempoolBlock.height].adjustment < 1 ? 'var(--red)' : '')">
+                    @if (cacheService.daCache[mempoolBlock.height].adjustment > 1) {
+                      <fa-icon class="retarget-sign up" [icon]="['fas', 'caret-up']" [fixedWidth]="true"></fa-icon>
+                    } @else if (cacheService.daCache[mempoolBlock.height].adjustment < 1) {
+                      <fa-icon class="retarget-sign" [icon]="['fas', 'caret-down']" [fixedWidth]="true"></fa-icon>
+                    }
+                    {{ (cacheService.daCache[mempoolBlock.height].adjustment - 1) * 100 | absolute | number: '1.2-2' }}
+                    <span class="symbol">%</span>
+                  </div>
+                </ng-container>
+                <ng-template #loadingAdjustment>
+                  <span class="skeleton-loader" style="max-width: 60px"></span>
+                </ng-template>
+              </td>
+            </tr>
           </tbody>
         </table>
         <app-fee-distribution-graph *ngIf="webGlEnabled" [transactions]="mempoolBlockTransactions$ | async" [feeRange]="mempoolBlock.isStack ? mempoolBlock.feeRange : []" [vsize]="mempoolBlock.blockVSize" ></app-fee-distribution-graph>

frontend/src/app/components/mempool-block/mempool-block.component.scss

@@ -36,3 +36,11 @@ h1 {
     margin: auto;
   }
 }
+
+.retarget-sign {
+  margin-right: -3px;
+  &.up {
+    position: relative;
+    top: 2px;
+  }
+}

frontend/src/app/components/mempool-block/mempool-block.component.ts

@@ -9,6 +9,7 @@ import { Observable, BehaviorSubject } from 'rxjs';
 import { SeoService } from '../../services/seo.service';
 import { seoDescriptionNetwork } from '../../shared/common.utils';
 import { WebsocketService } from '../../services/websocket.service';
+import { CacheService } from '../../services/cache.service';
 
 @Component({
   selector: 'app-mempool-block',
@@ -30,6 +31,7 @@ export class MempoolBlockComponent implements OnInit, OnDestroy {
     public stateService: StateService,
     private seoService: SeoService,
     private websocketService: WebsocketService,
+    public cacheService: CacheService,
     private cd: ChangeDetectorRef,
     @Inject(PLATFORM_ID) private platformId: Object,
   ) {
@@ -71,7 +73,7 @@ export class MempoolBlockComponent implements OnInit, OnDestroy {
         })
       );
 
-    this.mempoolBlockTransactions$ = this.stateService.liveMempoolBlockTransactions$.pipe(map(txMap => Object.values(txMap)));
+    this.mempoolBlockTransactions$ = this.stateService.liveMempoolBlockTransactions$.pipe(map(({transactions}) => Object.values(transactions)));
 
     this.network$ = this.stateService.networkChanged$;
   }

frontend/src/app/components/mempool-blocks/mempool-blocks.component.ts

@@ -1,10 +1,10 @@
 import { Component, OnInit, OnDestroy, ChangeDetectionStrategy, ChangeDetectorRef, HostListener, Input, OnChanges, SimpleChanges, Output, EventEmitter, ViewChild, ElementRef } from '@angular/core';
-import { Subscription, Observable, of, combineLatest } from 'rxjs';
+import { Subscription, Observable, of, combineLatest, throwError } from 'rxjs';
 import { MempoolBlock } from '../../interfaces/websocket.interface';
 import { StateService } from '../../services/state.service';
 import { EtaService } from '../../services/eta.service';
 import { Router } from '@angular/router';
-import { delay, filter, map, switchMap, tap } from 'rxjs/operators';
+import { delay, filter, map, retryWhen, switchMap, take, tap } from 'rxjs/operators';
 import { feeLevels } from '../../app.constants';
 import { specialBlocks } from '../../app.constants';
 import { RelativeUrlPipe } from '../../shared/pipes/relative-url/relative-url.pipe';
@@ -12,6 +12,8 @@ import { Location } from '@angular/common';
 import { DifficultyAdjustment, MempoolPosition } from '../../interfaces/node-api.interface';
 import { animate, style, transition, trigger } from '@angular/animations';
 import { ThemeService } from '../../services/theme.service';
+import { CacheService } from '../../services/cache.service';
+import { colorFromRetarget } from '../../shared/common.utils';
 
 @Component({
   selector: 'app-mempool-blocks',
@@ -93,6 +95,7 @@ export class MempoolBlocksComponent implements OnInit, OnChanges, OnDestroy {
   constructor(
     private router: Router,
     public stateService: StateService,
+    public cacheService: CacheService,
     private etaService: EtaService,
     private themeService: ThemeService,
     private cd: ChangeDetectorRef,
@@ -387,6 +390,37 @@ export class MempoolBlocksComponent implements OnInit, OnChanges, OnDestroy {
     this.mempoolBlocksFull.forEach((block, i) => this.mempoolBlockStyles.push(this.getStyleForMempoolBlock(block, i)));
   }
 
+  isDA(height: number): boolean {
+    if (this.chainTip === -1) {
+      return false;
+    }
+    const isDA = height % 2016 === 0 && this.stateService.network === '';
+    if (isDA && !this.cacheService.daCache[height]) {
+      this.cacheService.daCache[height] = { adjustment: 0 };
+      this.difficultyAdjustments$.pipe(
+        filter(da => !!da),
+        switchMap(da => {
+          const mempoolBlocksAvailable = this.chainTip && this.mempoolBlockStyles[height - this.chainTip - 1];
+          return mempoolBlocksAvailable ? of(da) : throwError(() => new Error());
+        }),
+        retryWhen(errors =>
+          errors.pipe(
+            delay(100),
+            take(3)
+          )
+        ),
+        tap(da => {
+          const adjustment = parseFloat((1 + da.difficultyChange / 100).toFixed(4));
+          if (adjustment !== this.cacheService.daCache[height].adjustment) {
+            this.cacheService.daCache[height].adjustment = adjustment;
+            this.mempoolBlockStyles[height - this.chainTip - 1].background = colorFromRetarget(adjustment);
+          }
+        })
+      ).subscribe();
+    }
+    return isDA;
+  }
+
   getStyleForMempoolBlock(mempoolBlock: MempoolBlock, index: number) {
     const emptyBackgroundSpacePercentage = Math.max(100 - mempoolBlock.blockVSize / this.stateService.blockVSize * 100, 0);
     const usedBlockSpace = 100 - emptyBackgroundSpacePercentage;
@@ -410,7 +444,7 @@ export class MempoolBlocksComponent implements OnInit, OnChanges, OnDestroy {
 
     return {
       'right': this.containerOffset + index * this.blockOffset + 'px',
-      'background': backgroundGradients.join(',') + ')'
+      'background': this.isDA(mempoolBlock.height) ? colorFromRetarget(this.cacheService.daCache[mempoolBlock.height]?.adjustment || 1) : backgroundGradients.join(',') + ')'
     };
   }
 

frontend/src/app/components/tracker/tracker.component.ts

@@ -747,7 +747,7 @@ export class TrackerComponent implements OnInit, OnDestroy {
 
   checkAccelerationEligibility() {
     if (this.tx) {
-      this.tx.flags = getTransactionFlags(this.tx);
+      this.tx.flags = getTransactionFlags(this.tx, null, null, this.tx.status?.block_time, this.stateService.network);
       const replaceableInputs = (this.tx.flags & (TransactionFlags.sighash_none | TransactionFlags.sighash_acp)) > 0n;
       const highSigop = (this.tx.sigops * 20) > this.tx.weight;
       this.eligibleForAcceleration = !replaceableInputs && !highSigop;

frontend/src/app/components/transaction/transaction.component.ts

@@ -901,7 +901,7 @@ export class TransactionComponent implements OnInit, AfterViewInit, OnDestroy {
       this.segwitEnabled = !this.tx.status.confirmed || isFeatureActive(this.stateService.network, this.tx.status.block_height, 'segwit');
       this.taprootEnabled = !this.tx.status.confirmed || isFeatureActive(this.stateService.network, this.tx.status.block_height, 'taproot');
       this.rbfEnabled = !this.tx.status.confirmed || isFeatureActive(this.stateService.network, this.tx.status.block_height, 'rbf');
-      this.tx.flags = getTransactionFlags(this.tx);
+      this.tx.flags = getTransactionFlags(this.tx, null, null, this.tx.status?.block_time, this.stateService.network);
       this.filters = this.tx.flags ? toFilters(this.tx.flags).filter(f => f.txPage) : [];
       this.checkAccelerationEligibility();
     } else {

frontend/src/app/docs/api-docs/api-docs-data.ts

@@ -3670,6 +3670,39 @@ export const restApiDocsData = [
       }
     }
   },
+  {
+    type: "endpoint",
+    category: "mining",
+    httpRequestMethod: "GET",
+    fragment: "get-difficulty-adjustment-by-height",
+    title: "GET Difficulty Adjustment",
+    description: {
+      default: "<p>Returns difficulty adjustment for the block at the specified <code>:blockHeight</code>. If no adjustment happened at that height, an empty response is returned.</p>"
+    },
+    urlString: "/v1/mining/difficulty-adjustment/:blockHeight",
+    showConditions: [""],
+    showJsExamples: showJsExamplesDefaultFalse,
+    codeExample: {
+      default: {
+        codeTemplate: {
+          curl: `/api/v1/mining/difficulty-adjustment/%{1}`,
+          commonJS: ``,
+          esModule: ``
+        },
+        codeSampleMainnet: {
+          esModule: [],
+          commonJS: [],
+          curl: [`756000`],
+          response: `{
+  "time": "2022-09-28T02:56:34.000Z",
+  "height": 756000,
+  "difficulty": 31360548173144.9,
+  "adjustment": 0.97863
+}`
+        },
+      }
+    }
+  },
   {
     type: "endpoint",
     category: "mining",

frontend/src/app/interfaces/node-api.interface.ts

@@ -239,7 +239,7 @@ export interface TransactionStripped {
   acc?: boolean;
   flags?: number | null;
   time?: number;
-  status?: 'found' | 'missing' | 'sigop' | 'fresh' | 'freshcpfp' | 'added' | 'added_prioritized' | 'prioritized' | 'censored' | 'selected' | 'rbf' | 'accelerated';
+  status?: 'found' | 'missing' | 'sigop' | 'fresh' | 'freshcpfp' | 'added' | 'added_prioritized' | 'prioritized' | 'added_deprioritized' | 'deprioritized' | 'censored' | 'selected' | 'rbf' | 'accelerated';
   context?: 'projected' | 'actual';
 }
 

frontend/src/app/interfaces/websocket.interface.ts

@@ -72,11 +72,13 @@ export interface MempoolBlockWithTransactions extends MempoolBlock {
 }
 
 export interface MempoolBlockDelta {
+  block: number;
   added: TransactionStripped[];
   removed: string[];
   changed: { txid: string, rate: number, flags: number, acc: boolean }[];
 }
 export interface MempoolBlockState {
+  block: number;
   transactions: TransactionStripped[];
 }
 export type MempoolBlockUpdate = MempoolBlockDelta | MempoolBlockState;

frontend/src/app/services/api.service.ts

@@ -315,6 +315,12 @@ export class ApiService {
       );
   }
 
+  getDifficultyAdjustmentByHeight$(height: number): Observable<any> {
+    return this.httpClient.get<any>(
+      this.apiBaseUrl + this.apiBasePath + `/api/v1/mining/difficulty-adjustment/${height}`
+    );
+  }
+
   getHistoricalHashrate$(interval: string | undefined): Observable<any> {
     return this.httpClient.get<any[]>(
         this.apiBaseUrl + this.apiBasePath + `/api/v1/mining/hashrate` +

frontend/src/app/services/cache.service.ts

@@ -23,6 +23,7 @@ export class CacheService {
   blockLoading: { [height: number]: boolean } = {};
   copiesInBlockQueue: { [height: number]: number } = {};
   blockPriorities: number[] = [];
+  daCache: { [height: number]: { adjustment: number, exact?: boolean } } = {};
 
   constructor(
     private stateService: StateService,
@@ -128,6 +129,7 @@ export class CacheService {
     this.blockLoading = {};
     this.copiesInBlockQueue = {};
     this.blockPriorities = [];
+    this.daCache = {};
   }
 
   getCachedBlock(height) {

frontend/src/app/services/state.service.ts

@@ -5,7 +5,7 @@ import { AccelerationDelta, HealthCheckHost, IBackendInfo, MempoolBlock, Mempool
 import { Acceleration, AccelerationPosition, BlockExtended, CpfpInfo, DifficultyAdjustment, MempoolPosition, OptimizedMempoolStats, RbfTree, TransactionStripped } from '../interfaces/node-api.interface';
 import { Router, NavigationStart } from '@angular/router';
 import { isPlatformBrowser } from '@angular/common';
-import { filter, map, scan, shareReplay } from 'rxjs/operators';
+import { filter, map, scan, share, shareReplay } from 'rxjs/operators';
 import { StorageService } from './storage.service';
 import { hasTouchScreen } from '../shared/pipes/bytes-pipe/utils';
 import { ActiveFilter } from '../shared/filters.utils';
@@ -131,6 +131,7 @@ export class StateService {
   latestBlockHeight = -1;
   blocks: BlockExtended[] = [];
   mempoolSequence: number;
+  mempoolBlockState: { block: number, transactions: { [txid: string]: TransactionStripped} };
 
   backend$ = new BehaviorSubject<'esplora' | 'electrum' | 'none'>('esplora');
   networkChanged$ = new ReplaySubject<string>(1);
@@ -143,7 +144,7 @@ export class StateService {
   mempoolInfo$ = new ReplaySubject<MempoolInfo>(1);
   mempoolBlocks$ = new ReplaySubject<MempoolBlock[]>(1);
   mempoolBlockUpdate$ = new Subject<MempoolBlockUpdate>();
-  liveMempoolBlockTransactions$: Observable<{ [txid: string]: TransactionStripped}>;
+  liveMempoolBlockTransactions$: Observable<{ block: number, transactions: { [txid: string]: TransactionStripped} }>;
   accelerations$ = new Subject<AccelerationDelta>();
   liveAccelerations$: Observable<Acceleration[]>;
   txConfirmed$ = new Subject<[string, BlockExtended]>();
@@ -231,29 +232,40 @@ export class StateService {
       }
     });
 
-    this.liveMempoolBlockTransactions$ = this.mempoolBlockUpdate$.pipe(scan((transactions: { [txid: string]: TransactionStripped }, change: MempoolBlockUpdate): { [txid: string]: TransactionStripped } => {
+    this.liveMempoolBlockTransactions$ = this.mempoolBlockUpdate$.pipe(scan((acc: { block: number, transactions: { [txid: string]: TransactionStripped } }, change: MempoolBlockUpdate): { block: number, transactions: { [txid: string]: TransactionStripped } } => {
       if (isMempoolState(change)) {
         const txMap = {};
         change.transactions.forEach(tx => {
           txMap[tx.txid] = tx;
         });
-        return txMap;
+        this.mempoolBlockState = {
+          block: change.block,
+          transactions: txMap
+        };
+        return this.mempoolBlockState;
       } else {
         change.added.forEach(tx => {
-          transactions[tx.txid] = tx;
+          acc.transactions[tx.txid] = tx;
         });
         change.removed.forEach(txid => {
-          delete transactions[txid];
+          delete acc.transactions[txid];
         });
         change.changed.forEach(tx => {
-          if (transactions[tx.txid]) {
-            transactions[tx.txid].rate = tx.rate;
-            transactions[tx.txid].acc = tx.acc;
+          if (acc.transactions[tx.txid]) {
+            acc.transactions[tx.txid].rate = tx.rate;
+            acc.transactions[tx.txid].acc = tx.acc;
           }
         });
-        return transactions;
+        this.mempoolBlockState = {
+          block: change.block,
+          transactions: acc.transactions
+        };
+        return this.mempoolBlockState;
       }
-    }, {}));
+    }, {}),
+    share()
+    );
+    this.liveMempoolBlockTransactions$.subscribe();
 
     // Emits the full list of pending accelerations each time it changes
     this.liveAccelerations$ = this.accelerations$.pipe(

frontend/src/app/services/websocket.service.ts

@@ -35,6 +35,7 @@ export class WebsocketService {
   private isTrackingAddresses: string[] | false = false;
   private isTrackingAccelerations: boolean = false;
   private trackingMempoolBlock: number;
+  private stoppingTrackMempoolBlock: any | null = null;
   private latestGitCommit = '';
   private onlineCheckTimeout: number;
   private onlineCheckTimeoutTwo: number;
@@ -203,19 +204,31 @@ export class WebsocketService {
     this.websocketSubject.next({ 'track-asset': 'stop' });
   }
 
-  startTrackMempoolBlock(block: number, force: boolean = false) {
+  startTrackMempoolBlock(block: number, force: boolean = false): boolean {
+    if (this.stoppingTrackMempoolBlock) {
+      clearTimeout(this.stoppingTrackMempoolBlock);
+    }
     // skip duplicate tracking requests
     if (force || this.trackingMempoolBlock !== block) {
       this.websocketSubject.next({ 'track-mempool-block': block });
       this.isTrackingMempoolBlock = true;
       this.trackingMempoolBlock = block;
+      return true;
     }
+    return false;
   }
 
-  stopTrackMempoolBlock() {
-    this.websocketSubject.next({ 'track-mempool-block': -1 });
+  stopTrackMempoolBlock(): void {
+    if (this.stoppingTrackMempoolBlock) {
+      clearTimeout(this.stoppingTrackMempoolBlock);
+    }
     this.isTrackingMempoolBlock = false;
-    this.trackingMempoolBlock = null;
+    this.stoppingTrackMempoolBlock = setTimeout(() => {
+      this.stoppingTrackMempoolBlock = null;
+      this.websocketSubject.next({ 'track-mempool-block': -1 });
+      this.trackingMempoolBlock = null;
+      this.stateService.mempoolBlockState = null;
+    }, 2000);
   }
 
   startTrackRbf(mode: 'all' | 'fullRbf') {
@@ -424,6 +437,7 @@ export class WebsocketService {
         if (response['projected-block-transactions'].blockTransactions) {
           this.stateService.mempoolSequence = response['projected-block-transactions'].sequence;
           this.stateService.mempoolBlockUpdate$.next({
+            block: this.trackingMempoolBlock,
             transactions: response['projected-block-transactions'].blockTransactions.map(uncompressTx),
           });
         } else if (response['projected-block-transactions'].delta) {
@@ -432,7 +446,7 @@ export class WebsocketService {
             this.startTrackMempoolBlock(this.trackingMempoolBlock, true);
           } else {
             this.stateService.mempoolSequence = response['projected-block-transactions'].sequence;
-            this.stateService.mempoolBlockUpdate$.next(uncompressDeltaChange(response['projected-block-transactions'].delta));
+            this.stateService.mempoolBlockUpdate$.next(uncompressDeltaChange(this.trackingMempoolBlock, response['projected-block-transactions'].delta));
           }
         }
       }

frontend/src/app/shared/address-utils.ts

@@ -17,6 +17,7 @@ export type AddressType = 'fee'
   | 'v0_p2wsh'
   | 'v1_p2tr'
   | 'confidential'
+  | 'anchor'
   | 'unknown'
 
 const ADDRESS_PREFIXES = {
@@ -188,6 +189,12 @@ export class AddressTypeInfo {
         const v = vin[0];
         this.processScript(new ScriptInfo('scriptpubkey', v.prevout.scriptpubkey, v.prevout.scriptpubkey_asm));
       }
+    } else if (this.type === 'unknown') {
+      for (const v of vin) {
+        if (v.prevout?.scriptpubkey === '51024e73') {
+          this.type = 'anchor';
+        }
+      }
     }
     // and there's nothing more to learn from processing inputs for other types
   }
@@ -197,6 +204,10 @@ export class AddressTypeInfo {
       if (!this.scripts.size) {
         this.processScript(new ScriptInfo('scriptpubkey', output.scriptpubkey, output.scriptpubkey_asm));
       }
+    } else if (this.type === 'unknown') {
+      if (output.scriptpubkey === '51024e73') {
+        this.type = 'anchor';
+      }
     }
   }
 

frontend/src/app/shared/common.utils.ts

@@ -170,8 +170,9 @@ export function uncompressTx(tx: TransactionCompressed): TransactionStripped {
   };
 }
 
-export function uncompressDeltaChange(delta: MempoolBlockDeltaCompressed): MempoolBlockDelta {
+export function uncompressDeltaChange(block: number, delta: MempoolBlockDeltaCompressed): MempoolBlockDelta {
   return {
+    block,
     added: delta.added.map(uncompressTx),
     removed: delta.removed,
     changed: delta.changed.map(tx => ({
@@ -239,3 +240,25 @@ export function md5(inputString): string {
     }
     return rh(a)+rh(b)+rh(c)+rh(d);
 }
+
+export function colorFromRetarget(da: number): string {
+  const minDA = 0.95;
+  const maxDA = 1.05;
+  const midDA = 1;
+
+  const red = { r: 220, g: 53, b: 69 };
+  const grey = { r: 108, g: 117, b: 125 };
+  const green = { r: 59, g: 204, b: 73 };
+
+  const interpolateColor = (color1, color2, ratio) => {
+    ratio = Math.min(1, Math.max(0, ratio));
+    const r = Math.round(color1.r + ratio * (color2.r - color1.r));
+    const g = Math.round(color1.g + ratio * (color2.g - color1.g));
+    const b = Math.round(color1.b + ratio * (color2.b - color1.b));
+    return `rgba(${r}, ${g}, ${b}, 0.7)`;
+  }
+
+  return da <= midDA ?
+    interpolateColor(red, grey, (da - minDA) / (midDA - minDA)) : 
+    interpolateColor(grey, green, (da - midDA) / (maxDA - midDA));
+}

frontend/src/app/shared/components/address-type/address-type.component.html

@@ -20,6 +20,9 @@
   @case ('multisig') {
     <span i18n="address.bare-multisig">bare multisig</span>
   }
+  @case ('anchor') {
+    <span>anchor</span>
+  }
   @case (null) {
     <span>unknown</span>
   }

frontend/src/app/shared/script.utils.ts

@@ -166,6 +166,7 @@ export const ScriptTemplates: { [type: string]: (...args: any) => ScriptTemplate
   ln_anchor: () => ({ type: 'ln_anchor', label: 'Lightning Anchor' }),
   ln_anchor_swept: () => ({ type: 'ln_anchor_swept', label: 'Swept Lightning Anchor' }),
   multisig: (m: number, n: number) => ({ type: 'multisig', m, n, label: $localize`:@@address-label.multisig:Multisig ${m}:multisigM: of ${n}:multisigN:` }),
+  anchor: () => ({ type: 'anchor', label: 'anchor' }),
 };
 
 export class ScriptInfo {
@@ -266,7 +267,7 @@ export function parseMultisigScript(script: string): undefined | { m: number, n:
   if (!opN) {
     return;
   }
-  if (!opN.startsWith('OP_PUSHNUM_')) {
+  if (opN !== 'OP_0' && !opN.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const n = parseInt(opN.match(/[0-9]+/)?.[0] || '', 10);
@@ -286,7 +287,7 @@ export function parseMultisigScript(script: string): undefined | { m: number, n:
   if (!opM) {
     return;
   }
-  if (!opM.startsWith('OP_PUSHNUM_')) {
+  if (opM !== 'OP_0' && !opM.startsWith('OP_PUSHNUM_')) {
     return;
   }
   const m = parseInt(opM.match(/[0-9]+/)?.[0] || '', 10);

frontend/src/app/shared/transaction.utils.ts

@@ -1,10 +1,10 @@
 import { TransactionFlags } from './filters.utils';
 import { getVarIntLength, opcodes, parseMultisigScript, isPoint } from './script.utils';
 import { Transaction } from '../interfaces/electrs.interface';
-import { CpfpInfo, RbfInfo } from '../interfaces/node-api.interface';
+import { CpfpInfo, RbfInfo, TransactionStripped } from '../interfaces/node-api.interface';
+import { StateService } from '../services/state.service';
 
 // Bitcoin Core default policy settings
-const TX_MAX_STANDARD_VERSION = 2;
 const MAX_STANDARD_TX_WEIGHT = 400_000;
 const MAX_BLOCK_SIGOPS_COST = 80_000;
 const MAX_STANDARD_TX_SIGOPS_COST = (MAX_BLOCK_SIGOPS_COST / 5);
@@ -89,10 +89,13 @@ export function isDERSig(w: string): boolean {
  *
  * returns true early if any standardness rule is violated, otherwise false
  * (except for non-mandatory-script-verify-flag and p2sh script evaluation rules which are *not* enforced)
+ *
+ * As standardness rules change, we'll need to apply the rules in force *at the time* to older blocks.
+ * For now, just pull out individual rules into versioned functions where necessary.
  */
-export function isNonStandard(tx: Transaction): boolean {
+export function isNonStandard(tx: Transaction, height?: number, network?: string): boolean {
   // version
-  if (tx.version > TX_MAX_STANDARD_VERSION) {
+  if (isNonStandardVersion(tx, height, network)) {
     return true;
   }
 
@@ -139,6 +142,8 @@ export function isNonStandard(tx: Transaction): boolean {
       }
     } else if (['unknown', 'provably_unspendable', 'empty'].includes(vin.prevout?.scriptpubkey_type || '')) {
       return true;
+    } else if (isNonStandardAnchor(tx, height, network)) {
+      return true;
     }
     // TODO: bad-witness-nonstandard
   }
@@ -203,6 +208,51 @@ export function isNonStandard(tx: Transaction): boolean {
   return false;
 }
 
+// Individual versioned standardness rules
+
+const V3_STANDARDNESS_ACTIVATION_HEIGHT = {
+  'testnet4': 42_000,
+  'testnet': 2_900_000,
+  'signet': 211_000,
+  '': 863_500,
+};
+function isNonStandardVersion(tx: Transaction, height?: number, network?: string): boolean {
+  let TX_MAX_STANDARD_VERSION = 3;
+  if (
+    height != null
+    && network != null
+    && V3_STANDARDNESS_ACTIVATION_HEIGHT[network]
+    && height <= V3_STANDARDNESS_ACTIVATION_HEIGHT[network]
+  ) {
+    // V3 transactions were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+    TX_MAX_STANDARD_VERSION = 2;
+  }
+
+  if (tx.version > TX_MAX_STANDARD_VERSION) {
+    return true;
+  }
+  return false;
+}
+
+const ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT = {
+  'testnet4': 42_000,
+  'testnet': 2_900_000,
+  'signet': 211_000,
+  '': 863_500,
+};
+function isNonStandardAnchor(tx: Transaction, height?: number, network?: string): boolean {
+  if (
+    height != null
+    && network != null
+    && ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[network]
+    && height <= ANCHOR_STANDARDNESS_ACTIVATION_HEIGHT[network]
+  ) {
+    // anchor outputs were non-standard to spend before v28.x (scheduled for 2024/09/30 https://github.com/bitcoin/bitcoin/issues/29891)
+    return true;
+  }
+  return false;
+}
+
 // A witness program is any valid scriptpubkey that consists of a 1-byte push opcode
 // followed by a data push between 2 and 40 bytes.
 // https://github.com/bitcoin/bitcoin/blob/2c79abc7ad4850e9e3ba32a04c530155cda7f980/src/script/script.cpp#L224-L240
@@ -289,7 +339,7 @@ export function isBurnKey(pubkey: string): boolean {
   ].includes(pubkey);
 }
 
-export function getTransactionFlags(tx: Transaction, cpfpInfo?: CpfpInfo, replacement?: boolean): bigint {
+export function getTransactionFlags(tx: Transaction, cpfpInfo?: CpfpInfo, replacement?: boolean, height?: number, network?: string): bigint {
   let flags = tx.flags ? BigInt(tx.flags) : 0n;
 
   // Update variable flags (CPFP, RBF)
@@ -439,7 +489,7 @@ export function getTransactionFlags(tx: Transaction, cpfpInfo?: CpfpInfo, replac
     flags |= TransactionFlags.batch_payout;
   }
 
-  if (isNonStandard(tx)) {
+  if (isNonStandard(tx, height, network)) {
     flags |= TransactionFlags.nonstandard;
   }
 
@@ -458,4 +508,83 @@ export function getUnacceleratedFeeRate(tx: Transaction, accelerated: boolean):
   } else {
     return tx.effectiveFeePerVsize;
   }
+}
+
+export function identifyPrioritizedTransactions(transactions: TransactionStripped[]): { prioritized: string[], deprioritized: string[] } {
+  // find the longest increasing subsequence of transactions
+  // (adapted from https://en.wikipedia.org/wiki/Longest_increasing_subsequence#Efficient_algorithms)
+  // should be O(n log n)
+  const X = transactions.slice(1).reverse(); // standard block order is by *decreasing* effective fee rate, but we want to iterate in increasing order (and skip the coinbase)
+  if (X.length < 2) {
+    return { prioritized: [], deprioritized: [] };
+  }
+  const N = X.length;
+  const P: number[] = new Array(N);
+  const M: number[] = new Array(N + 1);
+  M[0] = -1; // undefined so can be set to any value
+
+  let L = 0;
+  for (let i = 0; i < N; i++) {
+    // Binary search for the smallest positive l ≤ L
+    // such that X[M[l]].effectiveFeePerVsize > X[i].effectiveFeePerVsize
+    let lo = 1;
+    let hi = L + 1;
+    while (lo < hi) {
+      const mid = lo + Math.floor((hi - lo) / 2); // lo <= mid < hi
+      if (X[M[mid]].rate > X[i].rate) {
+        hi = mid;
+      } else { // if X[M[mid]].effectiveFeePerVsize < X[i].effectiveFeePerVsize
+        lo = mid + 1;
+      }
+    }
+
+    // After searching, lo == hi is 1 greater than the
+    // length of the longest prefix of X[i]
+    const newL = lo;
+
+    // The predecessor of X[i] is the last index of
+    // the subsequence of length newL-1
+    P[i] = M[newL - 1];
+    M[newL] = i;
+
+    if (newL > L) {
+      // If we found a subsequence longer than any we've
+      // found yet, update L
+      L = newL;
+    }
+  }
+
+  // Reconstruct the longest increasing subsequence
+  // It consists of the values of X at the L indices:
+  // ..., P[P[M[L]]], P[M[L]], M[L]
+  const LIS: TransactionStripped[] = new Array(L);
+  let k = M[L];
+  for (let j = L - 1; j >= 0; j--) {
+    LIS[j] = X[k];
+    k = P[k];
+  }
+
+  const lisMap = new Map<string, number>();
+  LIS.forEach((tx, index) => lisMap.set(tx.txid, index));
+
+  const prioritized: string[] = [];
+  const deprioritized: string[] = [];
+
+  let lastRate = 0;
+
+  for (const tx of X) {
+    if (lisMap.has(tx.txid)) {
+      lastRate = tx.rate;
+    } else {
+      if (Math.abs(tx.rate - lastRate) < 0.1) {
+        // skip if the rate is almost the same as the previous transaction
+      } else if (tx.rate <= lastRate) {
+        prioritized.push(tx.txid);
+      } else {
+        deprioritized.push(tx.txid);
+      }
+    }
+  }
+
+  return { prioritized, deprioritized };
 }

production/README.md

@@ -84,11 +84,11 @@ pkg install -y zsh sudo git screen curl wget neovim rsync nginx openssl openssh-
 
 ### Node.js + npm
 
-Build Node.js v16.16.0 and npm v8 from source using `nvm`:
+Build Node.js v20.17.0 and npm v9 from source using `nvm`:
 ```
-curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.1/install.sh | zsh
+curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.0/install.sh | zsh
 source $HOME/.zshrc
-nvm install v16.16.0 --shared-zlib
+nvm install v20.17.0 --shared-zlib
 nvm alias default node
 ```
 

unfurler/package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "mempool-unfurl",
-  "version": "3.0.0",
+  "version": "3.1.0-dev",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {

unfurler/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mempool-unfurl",
-  "version": "3.0.0",
+  "version": "3.1.0-dev",
   "description": "Renderer for mempool open graph link preview images",
   "repository": {
     "type": "git",