Microsoft will officially end support for Office LTSC 2021 on October 13, 2026. The company recommends that users transition to Microsoft 365 or Office 2024, as no official Extended Security Update program will be available for the 2021 version.
Security firm Acros Security, through its 0patch service, plans to provide unofficial security maintenance for Office 2021 for at least three years after the official support deadline. The company may extend this period further depending on user demand.
The 0patch service delivers micro-patches directly into the application memory without modifying original program files. This process allows users to apply fixes without restarting their computers or the Office software itself.
Access to these security updates is included in the 0patch PRO and Enterprise subscription plans. The Enterprise plan, which offers centralized management and single sign-on, is priced at €34.95 per computer annually, excluding taxes.