diff --git a/CMakeLists.txt b/CMakeLists.txt
index 57894e10c..cbd788f67 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -23,9 +23,9 @@ set( CMAKE_CXX_STANDARD 17 )
 set( CMAKE_CXX_EXTENSIONS ON )
 set( CXX_STANDARD_REQUIRED ON)
 
-set(VERSION_MAJOR 2)
+set(VERSION_MAJOR 4)
 set(VERSION_MINOR 0)
-set(VERSION_PATCH 4)
+set(VERSION_PATCH 0)
 #set(VERSION_SUFFIX rc3)
 
 if(VERSION_SUFFIX)
diff --git a/README.md b/README.md
index c260de864..cad39c190 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,13 @@
 ibc_plugin_eos
 -------------
+### IBC related softwares' version description
+There are three IBC related softwares, [ibc_contracts](https://github.com/boscore/ibc_contracts),
+[ibc_plugin_eos](https://github.com/boscore/ibc_plugin_eos) 
+and [ibc_plugin_bos](https://github.com/boscore/ibc_plugin_bos), 
+There are currently multiple major versions for all these three software repositories and between major versions maybe incompatible, 
+so the three repositories need to use the correct major version number to coordinate their work.
+For specific compatibility combinations, please refer to [README.md](https://github.com/boscore/ibc_contracts#ibc-related-softwares-version-description)
+
 
 ### Notes
 :warning:**The nodeos(build/program/nodeos/nodeos) build by this repository, can neither run as a block producer node nor as a api node**,
@@ -9,3 +17,5 @@ we add `chain_plug->chain().abort_block()` and `chain_plug->chain().drop_all_una
 recursively, and these transactions are sequentially dependent, so the ibc relay node's read mode must be "speculative",
 but it's very important that, when read contracts table state, ibc_plugin must read data in "read only mode",
 these two needs are conflicting, so we add above two functions to reach the goal.
+
+