Thanks for the info on Form 9325.

You could print out the "EF Instructions" which shows if the Form 7004 has been Filed and Accepted.

Or

Print the 7004 EF Worksheet and a box is X out if it was Accepted.

Thank you. I checked it but doesn't show the accepted dates.

I also tried the electronic filing client status history report but it shows only that no electronic filling records were found.

Partnerships are awkward.

I got the electronic filing client status history report. Forgot I "have to" be at the EF Center to get it.

Thank you. I seems that I checked but forgot to actually send it.

Ouch..

Good luck

Been there, done that.  

I do believe  Rev Proc 84-35  for abatement of late filing penalties is still available 

https://www.irs.gov/individuals/understanding-your-cp162a-notice

Great. Thank you!