diff --git a/README.md b/README.md
index 32b378f22..05fe32591 100755
--- a/README.md
+++ b/README.md
@@ -158,6 +158,7 @@ For previous versions, please read:
 
 ## V4 changes
 
+* v4.0, 2020-04-04, Merge RTC and GB28181, with bugs fixed. 4.0.21
 * v4.0, 2020-04-04, For [#307][bug #307], refine RTC latency from 600ms to 200ms. 4.0.20
 * v4.0, 2020-04-03, For [#307][bug #307], build SRTP with openssl to improve performance. 4.0.19
 * v4.0, 2020-03-31, For [#1500][bug #1500], support push stream by GB28181. 4.0.18
diff --git a/trunk/src/core/srs_core_version4.hpp b/trunk/src/core/srs_core_version4.hpp
index 9cf915bee..59147ea42 100644
--- a/trunk/src/core/srs_core_version4.hpp
+++ b/trunk/src/core/srs_core_version4.hpp
@@ -24,6 +24,6 @@
 #ifndef SRS_CORE_VERSION4_HPP
 #define SRS_CORE_VERSION4_HPP
 
-#define SRS_VERSION4_REVISION 20
+#define SRS_VERSION4_REVISION 21
 
 #endif