After you file

If it was a rental in 2023, Form 3115 does give a 'bonus' six months to be filed (see bottom of Revenue Procedure 2015-13).

 

However, what EXACTLY was the problem?  Form 3115 doesn't automatically fix everything.  It can only fix certain things.

 

https://www.irs.gov/pub/irs-drop/rp-15-13.pdf#page=43