diff --git a/.kokoro/build.sh b/.kokoro/build.sh
index 23a19d0..73b00ae 100755
--- a/.kokoro/build.sh
+++ b/.kokoro/build.sh
@@ -13,15 +13,12 @@ env | grep KOKORO
 
 cd github/google-auth-library-ruby/
 
-# Print out Ruby version
-ruby --version
+versions=($RUBY_VERSIONS)
 
 # Temporary workaround for a known bundler+docker issue:
 # https://github.com/bundler/bundler/issues/6154
 export BUNDLE_GEMFILE=
 
-RUBY_VERSIONS=("2.3.8" "2.4.5" "2.5.3" "2.6.1")
-
 # Capture failures
 EXIT_STATUS=0 # everything passed
 function set_failed_status {
@@ -30,12 +27,13 @@ function set_failed_status {
 
 if [ "$JOB_TYPE" = "release" ]; then
     git fetch --depth=10000
-    python3 -m pip install git+https://github.com/googleapis/releasetool
+    python3 -m pip install gcp-releasetool
     python3 -m releasetool publish-reporter-script > /tmp/publisher-script; source /tmp/publisher-script
     (bundle update && bundle exec rake kokoro:release) || set_failed_status
 else
-    for version in "${RUBY_VERSIONS[@]}"; do
+    for version in "${versions[@]}"; do
         rbenv global "$version"
+        echo "Using Ruby $version"
         (bundle update && bundle exec rake) || set_failed_status
     done
 fi