Per the EFAST2 system instructions, all delinquent and amended filings of Form 5500 must be submitted electronically through the EFAST2 system and can't be submitted on paper.
Refer to the DOL FAQs on EFAST2 Electronic Filing System for more information.
Can I e-file prior-year returns using Lacerte?
Benefit Plans in Lacerte follow the same rules as other filing types—you may e-file the current year plus two years prior. Lacerte doesn't offer electronic filing for returns over two years old.
How do I file returns over two years old?
For returns more than two years old, you should use the IFILE preparation software provided by the DOL. Refer to the IFILE User Guide or the EFAST for more information.
What is IFILE?
IFILE is the Form 5500 and Form 5500-SF annual return/report preparation and submission application that's located on the U.S. Department of Labor EFAST website.