diff --git a/lib/config/migration.js b/lib/config/migration.js
index 14c3bcd995bae90b98a02adb56fc555f0ce2f4c8..3d9c90efead1044a40aff5b729a20b67d8264927 100644
--- a/lib/config/migration.js
+++ b/lib/config/migration.js
@@ -365,6 +365,7 @@ function migrateConfig(config) {
         }
       } else if (
         (key === 'prBody' || key.startsWith('commitMessage')) &&
+        val &&
         (val.includes('currentVersion') || val.includes('newVersion'))
       ) {
         isMigrated = true;