The 2024 Forms W-2, W-2AS, W-2GU, and W-2VI (that posted to IRS.gov in December of 2023) have been revised. The text of box 12, Code S, under Instructions for Employee has been revised to remove "(not included in box 1)". Although salary reduction contributions to a SIMPLE IRA plan are not included in box 1, salary reduction contributions to a Roth SIMPLE IRA must be included in box 1. See Q&A K-5 of Notice 2024-2, 2024-2 I.R.B. 316, January 8, 2024.
The revised forms were posted on January 9, 2024. Please disregard any 2024 Forms W-2, W-2AS, W-2GU, or W2VI you may have downloaded or used before January 9, 2024.
All paper 2024 Forms W-2, W-2AS, W-2GU, and W-2VI will have the above change when they become available.