diff --git a/README.md b/README.md
index 49c7b7d..f1d3095 100644
--- a/README.md
+++ b/README.md
@@ -39,8 +39,10 @@ Recent Releases
 ####??-Mar-2014 - version 1.6.3 (JDK 1.6+ compatible, Netty 4.0.17)
 Fixed - AckCallback handling during client disconnect  
 Fixed - unauthorized handshake HTTP code changed to 401  
+__Breaking api change__ - Configuration.heartbeatThreadPoolSize setting removed  
 Feature - annotated Spring beans support via _SpringAnnotationScanner_  
 Feature - common exception listener  
+Improvement - _ScheduledExecutorService_ replaced with _HashedWheelTimer_  
 
 ####08-Feb-2014 - version 1.6.2 released (JDK 1.6+ compatible, Netty 4.0.15)
 Fixed - wrong namespace client disconnect handling