diff --git a/.travis.yml b/.travis.yml
index 3e6af669..72de1df3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -82,6 +82,8 @@ matrix:
   include:
     - php: 5.6
       env: DB=mysql
+    - php: 5.6
+      env: DB=mysql;CORE_BRANCH=stable9.1
     - php: 5.6
       env: DB=pgsql
     - php: 5.6
@@ -89,7 +91,7 @@ matrix:
     - php: 5.6
       env: DB=mysql;CODECHECK=2
     - php: 5.6
-      env: DB=mysql;JSTESTS=1;CODECHECK=1
+      env: DB=mysql;JSTESTS=1;
     - php: 7.0
       env: DB=mysql;CODECHECK=1
     - php: 7.0