diff --git a/bip-0138.md b/bip-0138.md
index ad609276..76948e8a 100644
--- a/bip-0138.md
+++ b/bip-0138.md
@@ -566,6 +566,11 @@ contains test vectors for BIP380 descriptor backup documents.
 [bip388.json](./bip-0138/test_vectors/bip388.json)
 contains test vectors for BIP388 wallet policy backup documents.  
 
+## Backward Compatibility
+
+This BIP defines a new format and changes no existing one. Liana wallet uses an early
+version of this BIP, which is not compatible: its magic is `BEB` rather than `BIP138`.
+
 ## Acknowledgements
 
 // TBD