diff --git a/CHANGELOG b/CHANGELOG
index 891652f1e..668bbfb31 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -29,6 +29,10 @@
 
 * Pending changes since 16.1.2
 ** API changes
+- mp:holding-lock-p: introduce new function for multiprocessing.
+Function verifies, if lock is hold by the thread which calls the
+function. Usage: =(mp:holding-lock-p my-lock)=.
+
 - make-random-state: fix problem with simple-vectors
 The correct initialization types for =make-random-state= are:
 =(OR RANDOM-STATE FIXNUM (MEMBER T NIL))=.