Microsoft shuts down legacy SharePoint app authentication
Microsoft will retire SharePoint Add-In authentication using Azure Access Control Services on April 2 2026. Any provider-hosted add-ins relying on this legacy system will stop functioning entirely on that date. Developers and administrators must migrate these custom solutions to Microsoft Entra ID authentication. The update requires configuring new tenant IDs and client secrets to maintain access. The transition preserves existing application logic but fundamentally changes how these apps request and renew access tokens behind the scenes.
For years companies relied on third-party contractors to build custom SharePoint solutions using provider-hosted add-ins. These bespoke apps quietly handled everything from document workflows to custom forms while relying on an outdated authentication model that most current IT teams forgot existed. The April 2026 deadline turns that forgotten technical debt into an immediate operational risk. When these legacy apps break users will flood the IT desk with support tickets for systems the current administrators did not build and cannot easily fix without developer intervention.
Analysis
Stop worrying about how to rewrite code you did not write. Run the Microsoft 365 Assessment Tool today to hunt down every legacy add-in hiding in your tenant. Once you find them you can decide whether to hire a developer to build the Entra ID fix or finally replace that ancient custom app with a simple Power Automate workflow.
Pulse published by Collab365 Spaces. Cite as "Microsoft shuts down legacy SharePoint app authentication", Collab365 Spaces.