Why do you believe you've been 'hacked'? Have you found coins/funds missing from a wallet?
I had the same thing happen to me as others have said. When using electrum a message appeared saying I need to update the app. Then after redownloading I saw my funds had been sent to another account.
If you downloaded from anywhere but electrum.org then most likely.
You should never download anything if you get a warning like this. It could be a developer scamming at best.
Yeh wish Id know not to before though. Im guessing theres nothing I can do about it now?