Microsoft 365 to Disable Legacy Authentication Protocols for Enhanced Security in 2025

Here’s a summary of the main points from the Neowin article and Microsoft’s update:

What’s Happening?​

• Microsoft 365 will disable legacy authentication protocols (Relying Party Suite [RPS] and FrontPage Remote Procedure Call [FPRPC]) for file access.
• This affects Microsoft 365 and Office apps, SharePoint, and OneDrive.

Timeline​

• The change starts mid-July 2025.
• The rollout will be completed by August 2025.

Why is Microsoft Doing This?​

• Security: Legacy protocols like RPS and FPRPC are considered insecure—they can be brute-forced, phished, and are vulnerable to various exploits.
• This is in line with Microsoft’s Secure Future Initiative (SFI).

Impact​

• Applications/services using RPS or FPRPC for browser-based authentication to open Office files will no longer work.
• No licensing changes are required—the protocol change will be applied by default.
• Admin consent will be required for third-party access to files/sites after the change.
• IT admins will need to set up/administer consent workflows for these operations.

What Should IT Admins Do?​

• Review systems/integrations that use RPS/FPRPC for file access in Office 365, SharePoint, and OneDrive.
• Update or replace any third-party apps or custom integrations that use these protocols.
• Follow Microsoft’s documentation to configure admin consent workflow for third-party access.

Source: Neowin - Microsoft 365 will soon disable outdated authentication protocols for file access
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Source: Neowin Microsoft 365 will soon disable outdated authentication protocols for file access