Internal Revenue Service (IRS) Revenue Procedure 2017-18 provides that the last day of the remedial amendment period for 403(b) plans is March 31, 2020.
In April 2013, the agency issued Revenue Procedure 2013-22 establishing a pre-approved plan program for 403(b)s and offered a remedial amendment period for 403(b) plan documents.
Though 403(b) plan sponsors had to adopt a written plan by December 31, 2009, they will be able to restate their plans to adopt one of the prototypes when the IRS makes them available. Those plan sponsors that did adopt their written plans by the 2009 deadline will also be given a remedial amendment period to retroactively correct plan operational failures—i.e. plan operational practices that did not conform to document requirements or features.
It is important to note that the pre-approved prototype plans have not yet been made available.