---
slug: "azure-functions-runtime-1-x-end-of-support"
title: "Azure Functions: runtime version 1.x end of support"
summary: "End of support date for version 1.x of the Azure Functions runtime: 14 Sep 2026. The version can still be used after that date but no longer receives support or software and security updates."
cloud: "azure"
service: "Azure Functions"
service_slug: "functions"
category: "feature"
type: "end_of_support"
announced_date: "2023-09-29"
effective_date: "2026-09-14"
effective_precision: "day"
replacement: "Azure Functions runtime version 4.x"
affected_versions: ["1.x"]
source_url: "https://azure.microsoft.com/updates?id=support-for-the-1x-version-of-azure-functions-ends-14-september-2026"
extra_source_urls: ["https://aka.ms/v1-af-dotnet-migration","https://learn.microsoft.com/en-us/azure/azure-functions/functions-versions"]
vendor_ref: "support-for-the-1x-version-of-azure-functions-ends-14-september-2026"
last_checked_at: "2026-11-12T09:55:19.345Z"
created_at: "2026-11-13T13:36:44.208Z"
updated_at: "2026-11-13T13:36:44.208Z"
url: "https://eolwatch.dev/items/azure-functions-runtime-1-x-end-of-support"
short_url: "https://eolwatch.dev/i/k"
markdown_url: "https://eolwatch.dev/items/azure-functions-runtime-1-x-end-of-support.md"
json_url: "https://eolwatch.dev/items/azure-functions-runtime-1-x-end-of-support.json"
source_note: null
---

# Azure Functions: runtime version 1.x end of support

End of support date for version 1.x of the Azure Functions runtime: 14 Sep 2026. The version can still be used after that date but no longer receives support or software and security updates.

- Effective date: 14 Sep 2026
- Cloud: [Azure](https://eolwatch.dev/cloud/azure.md)
- Service: [Azure Functions](https://eolwatch.dev/services/azure/functions.md)
- Type: End of support
- Category: [Feature](https://eolwatch.dev/categories/features.md)
- Affected versions: 1.x
- Replacement: Azure Functions runtime version 4.x
- Announced: 29 Sep 2023
- Official source: [azure.microsoft.com](https://azure.microsoft.com/updates?id=support-for-the-1x-version-of-azure-functions-ends-14-september-2026)
- Last checked: 12 Nov 2026

## What breaks

Support for version 1.x of the Azure Functions runtime ends on 14 Sep 2026. Version 1.x can still be used beyond that date, but it is no longer supported and no longer receives software or security updates.

## Who is affected

### Affected versions

- `1.x`

### Matching resource types

- `azurerm_windows_function_app`

### Fields the check reads

- `functions_extension_version`

### Detected by the estate check from

- Terraform state or plan (JSON)

## What to do

To stay on a supported version, [migrate to version 4.x of the Azure Functions runtime](https://aka.ms/v1-af-dotnet-migration) by the end of support date.

## Replacement

Azure Functions runtime version 4.x

## Sources

- [Official source](https://azure.microsoft.com/updates?id=support-for-the-1x-version-of-azure-functions-ends-14-september-2026) (azure.microsoft.com, Official)
- [Additional source](https://aka.ms/v1-af-dotnet-migration) (aka.ms, Official)
- [Additional source](https://learn.microsoft.com/en-us/azure/azure-functions/functions-versions) (learn.microsoft.com, Official)

Last checked against the first source in this list on 12 Nov 2026.

Page: https://eolwatch.dev/items/azure-functions-runtime-1-x-end-of-support | JSON: https://eolwatch.dev/items/azure-functions-runtime-1-x-end-of-support.json

The text on this page is drafted with AI assistance from the vendor's text, checked against the official source and approved by a person before it is published.