diff --git a/build.gradle b/build.gradle
index a1e00e01d60..1337dac14a3 100644
--- a/build.gradle
+++ b/build.gradle
@@ -59,7 +59,7 @@ configure(allprojects) { project ->
 	ext.log4jVersion         = '2.9.0'
 	ext.nettyVersion         = "4.1.15.Final"
 	ext.okhttp3Version       = "3.9.0"
-	ext.reactorVersion       = "Bismuth-BUILD-SNAPSHOT"
+	ext.reactorVersion       = "Bismuth-M4"
 	ext.rxjavaVersion        = '1.3.0'
 	ext.rxjavaAdapterVersion = '1.2.1'
 	ext.rxjava2Version       = '2.1.3'