diff --git a/.kokoro/build.sh b/.kokoro/build.sh
index 2f84030..4c7cc45 100755
--- a/.kokoro/build.sh
+++ b/.kokoro/build.sh
@@ -20,7 +20,7 @@ ruby --version
 # https://github.com/bundler/bundler/issues/6154
 export BUNDLE_GEMFILE=
 
-RUBY_VERSIONS=("2.3.7" "2.4.4" "2.5.1")
+RUBY_VERSIONS=("2.3.8" "2.4.5" "2.5.3")
 
 # Capture failures
 EXIT_STATUS=0 # everything passed