RELEASE_NOTES.md in btcruby-1.5.1 vs RELEASE_NOTES.md in btcruby-1.6

@@ -1,10 +1,17 @@
 
 BTCRuby Release Notes
 =====================
 
+1.6 (January 15, 2015)
+-------------------------
+
+* `BTC::Mnemonic` implements read-only part of BIP44.
+* `BTC::Keychain` implements utility methods to derive BIP44 keys.
+
+
 1.5.1 (December 30, 2015)
------------------------
+-------------------------
 
 * `BTC::TransactionSignatureChecker` accepts `version` and `amount` to support different hashing schemes (e.g. segwit) and passes them to `BTC::Transaction#signature_hash` function.
 
 
 1.5 (November 29, 2015)