One of the best things about Azure is that Microsoft will regularly release new updates, features and security patches, meaning it’s kept constantly up to date.

The downside to that however (and it’s not really much of a downside) is that occasionally older products will come out of support as they get retired.

As of 14th September 2026, support for version 1.x of the Azure Functions runtime will end.

You’ll still be able to use that version beyond then, but it won’t be supported anymore and won’t receive any more software or security updates, potentially causing a security risk to your organisation.

To stop that from happening, Microsoft are advising everyone to migrate over to version 4.x of the Azure Functions runtime before then and have given plenty of notice to let everyone complete the migration in a controlled fashion.

The new 4.x Azure Functions runtime  comes with a whole host of new benefits, such as:

• Support for additional target framework versions, including .NET Framework 4.8, .NET 6 and .NET 7
• The Ability to work with the latest Azure SDKs
• Enhanced monitoring options
• Improved reliability, throughput and cold-start performance.

What To Do Next

You’ve a couple of options on what to do next.

To make sure your function apps continue to be supported you can migrate everything yourself to version 4.x of Azure Functions runtime before 14.09.2026, with full instructions here >>

Or, you can get in touch with a Microsoft Partner such as FormusPro and we’ll be happy to support you through the migration process (you can find contact details at the bottom of this page). which lets face it, will be a lot easier!