diff --git a/build/conf/classVersions.txt b/build/conf/classVersions.txt
index 3701c245698d..fd1514b438f4 100644
--- a/build/conf/classVersions.txt
+++ b/build/conf/classVersions.txt
@@ -49,8 +49,8 @@
 1.6 => lib/external-system-rt.jar
 - => lib/jshell-frontend.jar
 
-1.7 => plugins/gradle/lib/gradle-tooling-extension-api.jar
-1.7 => plugins/gradle/lib/gradle-tooling-extension-impl.jar
+1.6 => plugins/gradle/lib/gradle-tooling-extension-api.jar
+1.6 => plugins/gradle/lib/gradle-tooling-extension-impl.jar
 
 1.6 => plugins/maven/lib/maven-server-api.jar
 1.6 => plugins/maven/lib/maven2-server-impl.jar