Function apps on the .NET in-process model - support ends Nov 10, 2026

What LeftSize checks

Detect Linux function apps that run C# on the .NET in-process model. Support for the in-process model ends on November 10, 2026. Migrate to the isolated worker model.

Why it matters

Missed retirement and end-of-support dates turn into forced upgrades, outages or extended support charges at a moment you did not choose.

What you get in the GitHub issue

LeftSize runs this check from a scheduled GitHub Action with a read-only identity in your Azure account and opens one issue per scope, updated on every scan. The issue includes:

• The affected resources, grouped per subscription, resource group or account and region
• Background on why it was flagged and when it is a false positive
• Cost and operational impact of fixing it
• Alternative approaches and their trade-offs
• Step-by-step remediation with safety checks
• Ready-to-run fix scripts (CLI, PowerShell or Terraform where available)
• Snooze, ignore or report a finding with a comment on the issue

Official references

• https://learn.microsoft.com/en-us/azure/azure-functions/migrate-dotnet-to-isolated-model
• https://learn.microsoft.com/en-us/azure/azure-functions/migrate-version-3-version-4