diff --git a/actions/bump-version/action.yaml b/actions/bump-version/action.yaml
index 483a3ea..c925de4 100644
--- a/actions/bump-version/action.yaml
+++ b/actions/bump-version/action.yaml
@@ -33,7 +33,7 @@ runs:
           cmd="$cmd --prerelease $PRERELEASE"
         fi
 
-        if [ -n "$MAJOR_VERSION_ZERO" ]; then
+        if [ "$MAJOR_VERSION_ZERO" = "true" ]; then
           cmd="$cmd --major-version-zero"
         fi
 
@@ -52,7 +52,7 @@ runs:
           cmd="$cmd --prerelease $PRERELEASE"
         fi
 
-        if [ -n "$MAJOR_VERSION_ZERO" ]; then
+        if [ "$MAJOR_VERSION_ZERO" = "true" ]; then
           cmd="$cmd --major-version-zero"
         fi