fixes #4083 (#4148)
diff --git a/.travis.yml b/.travis.yml
index b35f0ebbf2e..ca06f07d04e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -94,11 +94,13 @@ matrix:
 
 
 # Only build pushes to the master branch, PRs, and branches beginning with
-# `test-`. This reduces the number of simultaneous Travis runs, which speeds
-# turnaround time on review since there is a cap of 5 simultaneous runs.
+# `test-` or of the form `digit(s).digit(s).x`. This reduces the number of
+# simultaneous Travis runs, which speeds turnaround time on review since there
+# is a cap of on the number of simultaneous runs.
 branches:
   only:
     - master
+    - /^\d+\.\d+\.x$/
     - /^test-.*$/
 
 # container-based infrastructure

(cherry picked from commit dd8253b3d69329b6f23662eab4499a17dc4da9e7)