SharePoint Online Add-Ins Retired April 2, 2026 — VirtoSoftware Apps Remain Unaffected

Microsoft retired SharePoint Online Add-Ins on April 2, 2026, marking the end of an entire generation of SharePoint extensions that once powered custom forms, workflows, dashboards, and more. That date has passed — and if you haven’t migrated yet, the Add-Ins you relied on are already switched off.

When Azure Access Control Services (ACS) shut down on April 2, 2026, any SharePoint Add-Ins that depended on ACS authentication stopped working immediately. There was no grace period, no phased rollout, and no “fix later” option.

Let’s break down what happened, how to check if you’re affected, and how to act fast to bring back the SharePoint tools that went dark.

What’s Happening and Why

SharePoint Add-Ins were introduced in the SharePoint 2013 era to extend SharePoint functionality securely without running custom code on Microsoft’s servers. They allowed developers to create “plug-in” applications (Add-Ins) that ran separately, often hosted on Azure or external servers.

However, this model relies on Azure ACS tokens for authentication. Microsoft began deprecating ACS several years ago, replacing it with more secure, modern frameworks such as SharePoint Framework (SPFx) and Microsoft Entra ID app registrations (formerly Azure AD).

In short:

• ACS authentication ended April 2, 2026
• SharePoint Online Add-Ins no longer function
• SharePoint Server (on-premises) is not affected

This change impacts both custom-developed Add-Ins and third-party marketplace apps that still depend on ACS.

How to Know If You’re Affected

If your team built or installed custom apps for SharePoint Online before 2024, chances are you had Add-Ins running until April 2, 2026 — even if you’ve long forgotten about them.

Look for these warning signs:

• You see “Add-Ins” listed under Site contents → Site apps/Add-ins
• You use classic SharePoint web parts for forms, dashboards, or trackers
• You rely on provider-hosted apps or integrations hosted outside M365
• You installed products from the SharePoint marketplace before 2024

Even if these tools worked perfectly until then, they failed overnight on April 2.

Your 20-Day Emergency Plan

If anything still depends on Add-Ins, act quickly and systematically.

Day 1–2: Inventory Everything

Start with a full inventory of your Add-Ins and app dependencies.

For users:

• Visit Site contents → Site apps/Add-ins
• Take screenshots of everything that appears

For administrators:

• Run the M365 Assessment Tool for Add-Ins ACS to detect active Add-Ins across your tenant
• Export the App Catalog list
• Run PowerShell:

Get-SPOTenantAppInfo | Export-Csv AddInsInventory.csv

Then classify what you find:

• ❌ Critical — used daily (for operations, forms, document routing, etc.)
• ⚠️ Important — used weekly or monthly
• ✅ Unused — remove immediately

Day 3–6: Map Replacements

Once you’ve identified dependencies, start mapping replacements for each Add-In category (example):

If you’re unsure whether your current app has an SPFx version, contact VirtoSoftware support now. All VirtoSoftware apps have updated SPFx releases ready for SharePoint Online.

Day 7–10: Deploy and Test

• Add SPFx apps to your App Catalog
• Deploy to a test site and recreate your top 3 use cases
• Update site links and quick launch items
• Have at least 5 power users test and confirm that everything works as expected

Day 11–14: Roll Out to Production

Once testing is complete, start deployment to production sites — prioritizing high-impact ones first. Notify teams clearly:

🚨 “The old Add-In is retired — use the new SPFx version.”
📍 [Provide the new web part location]
✅ [List three key functions verified]
🧑‍💻 Support contact: [IT or admin name]

Keep communication consistent to avoid support confusion during the transition.

Day 15–20: Final Sweep

Run one last check to ensure no Add-Ins remain active:

Connect-SPOService
Set-SPOTenant -DenyAddIns $true
Set-SPOTenant -IsSharePointAddInsDisabled $true

Then, clean up your environment:

• Purge old entries from the App Catalog
• Verify there are no open tickets or broken links
• Save a migration log for compliance and audit purposes

By the end of the sweep, you should be 100% SPFx-based, with nothing left that depended on the retired Add-Ins.

Virto Emergency Migration Kit

VirtoSoftware offers ready-to-deploy modern replacements for nearly all legacy Add-In functions:

• Virto M365 Productivity Kit bundle — secure, all-in-one solution for SharePoint Online and Teams integrations.
• Virto M365 Apps — updated SPFx web parts available directly through Microsoft AppSource.

If your organization depended on Add-Ins for daily workflows, don’t wait another day — the migration path is clear, and the deadline has passed.