Explained: AutoUpdate for Cracked Apps

Is impossible.

Updating cracked apps will never be as easy as automatic unless app-cracking becomes automated with every submission to Apple’s AppStore, which isn’t likely to happen. Apps are bought, cracked, and uploaded to various websites manually by people; when an app gets an update, crackers update their apps, crack them, and upload again. Not all apps are cracked and not all cracks get updated.

If you want to use cracked apps you have to bear the consequence of manually finding an updated .ipa to update your apps yourself.