is GSR10 mandatory still now?

is GSTR10 mandatory still now?
I got registration cancelled on 29/8/18. but didn't know to file such return (gstr10). Now try to file annual return, found "final return " option in service section. Then try to file gstr10(due date was 31/12/18), found 10k aslate fee were imposed there. Didnt get any notice/ order/ reminder from concerned office or found in portal. If gstr10 has to file, how to file return without penalty .?

reply plzz..