diff --git a/ChangeLog b/ChangeLog
index 2789704..122cd2c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -23,6 +23,9 @@
    * Add support for alternative CSR headers, as used by Microsoft and defined
      in RFC 7468. Found by Michael Ernst. Fixes #767.
    * Correct many misspellings. Fixed by MisterDA #2371.
+   * Provide an abstraction of vsnprintf to allow alternative implementations
+     for platforms that don't provide it. Based on contributions by Joris Aerts
+     and Nathaniel Wesley Filardo.
 
 = mbed TLS 2.16.0 branch released 2018-12-21