Plan document not updated for final 403(b) regulations

Tax-exempt employer established 403(b) plan effective 7/1/1998, and amended and restated effective 7/1/1999 on a individually designed plan document.  Document was not updated to comply with final 403(b) regulations, EGTRRA, PPA, HEART, and WRERA.

What corrective action should the employer take to address these document failures?

Adopt the correct document(s) and file under VCP.

Quote

Rev. Proc. 2018-52, 6.10 (3) Correction for failure to adopt a written 403(b) Plan timely. A failure to adopt a written 403(b) Plan timely in accordance with the final regulations under § 403(b) and Notice 2009-3 may be corrected under VCP and Audit CAP. The issuance of a compliance statement or closing agreement for the failure to adopt a written 403(b) Plan timely will result in the written 403(b) Plan being treated as if it had been adopted timely for the purpose of making available the extended remedial amendment period set forth in Rev. Proc. 2017-18, 2017-5 I.R.B 743. However, the issuance of a compliance statement or closing agreement does not constitute a determination as to whether the written plan, as drafted, complies with the applicable requirements of § 403(b) of the Code and the final 403(b) regulations.

I don't know if a current pre-approved document would work by itself, or if you would need to do a 2009 vintage document and a current one.  Our document provider has said interim amendments were not required for 403(b)s.