diff --git a/lib/message.sh b/lib/message.sh
index 124e971..3b86f52 100644
--- a/lib/message.sh
+++ b/lib/message.sh
@@ -32,8 +32,8 @@ make_push_status() {
   COMPARE=""
   ADDITIONAL_INFO=""
 
-  if [[ -n "${BUMPER_CURRENT_VERSION}" ]]; then
-    COMPARE="**Changes**: [${BUMPER_CURRENT_VERSION}...${BUMPER_NEXT_VERSION}](${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/compare/${BUMPER_CURRENT_VERSION}...${BUMPER_NEXT_VERSION})"
+  if [[ -n "${BUMPER_CURRENT_VERSION:-}" ]]; then
+    COMPARE="**Changes**: [${BUMPER_CURRENT_VERSION:-}...${BUMPER_NEXT_VERSION}](${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY}/compare/${BUMPER_CURRENT_VERSION:-}...${BUMPER_NEXT_VERSION})"
   fi
 
   if [[ -n "${INPUT_BUMP_SEMVER}" && "${INPUT_BUMP_SEMVER}" == "true" ]]; then