Email from Microsoft asking to Migrate to version 4.x of the Azure Functions runtime

Question

Email from Microsoft asking to Migrate to version 4.x of the Azure Functions runtime

Bhardwaj, Sumit 0

Hello,

I recently received an email from Microsoft advising me to migrate to version 4.x of the Azure Functions runtime for my subscription.

However, after reviewing my subscription, I could not find any hosted Azure Function Apps. Could you please confirm whether this notification was sent in error, or if there are any resources associated with my subscription that require this migration?
Thank you for your assistance.

Regards
Sumit

Vallepu Venkateswarlu 10,510 Reputation points Microsoft External Staff Moderator

2026-07-28T12:36:10.6666667+00:00
Hi Bhardwaj, Sumit,

Welcome to Microsoft Q&A Platform.
I understand that you received an email advising you to migrate to Azure Functions Runtime v4.

Could you please provide the following information in private message?

A copy or screenshot of the notification email you received.

Please confirm that you have reviewed all the resource groups within the subscription and were unable to locate any Azure Function Apps.

If the notification includes the Function App name or Resource ID, kindly verify whether that Function App exists in another Azure subscription associated with your account or tenant.

Once we receive the above information, we'll investigate whether the notification is applicable to your environment or determine if any further action is required.

We look forward to your response.

2 answers

Your answer

Vallepu Venkateswarlu 10,510 Reputation points Microsoft External Staff Moderator

2026-07-28T12:36:10.6666667+00:00

Hi Bhardwaj, Sumit,

Welcome to Microsoft Q&A Platform.
I understand that you received an email advising you to migrate to Azure Functions Runtime v4.

Could you please provide the following information in private message?

A copy or screenshot of the notification email you received.

Please confirm that you have reviewed all the resource groups within the subscription and were unable to locate any Azure Function Apps.

If the notification includes the Function App name or Resource ID, kindly verify whether that Function App exists in another Azure subscription associated with your account or tenant.

Once we receive the above information, we'll investigate whether the notification is applicable to your environment or determine if any further action is required.

We look forward to your response.

Answer 1

kagiyama yutaka 4,835

I think that if your subscription shows no Function Apps in the portal, and Azure Resource Graph resources | where type == "microsoft.web/sites" | where kind contains "functionapp" returns nothing, and Get-AzFunctionApp also returns zero across all subscriptions, then there is no Function App that Microsoft expects you to migrate. After these checks, attaching the email to a support ticket is the safest next step.

Vallepu Venkateswarlu 10,510 Reputation points Microsoft External Staff Moderator

2026-07-29T09:48:36.0366667+00:00

Hi Bhardwaj, Sumit,

Please review the response posted by kagiyama yutaka. If it does not resolve your issue or you need further clarification, please let us know. We'll be happy to assist you further and work with you toward a resolution.

Answer 2

The notification can still be valid even when no Azure Function Apps are currently visible in the subscription.

A supported way to verify this is to check for function apps that are still configured for retired runtime versions. Azure Functions runtime versions 2.x and 3.x reached end of extended support on December 13, 2022, and apps still on v3 on Linux Consumption stop running after September 30, 2026.

Use one of these checks:

In the Azure portal:
- Open the Function App area for the subscription.
- Go to Diagnose and solve problems.
- Search for Updating Function App Language or Runtime Version.
- In the diagnostic report, select List All Function App > View Details.
- Apply filters and select Show to list function apps in the current subscription.
In PowerShell, list apps targeting v3:

$Subscription = '<YOUR SUBSCRIPTION ID>' 

Set-AzContext -Subscription $Subscription | Out-Null

$FunctionApps = Get-AzFunctionApp

$AppInfo = @{}

foreach ($App in $FunctionApps)
{
     if ($App.ApplicationSettings["FUNCTIONS_EXTENSION_VERSION"] -like '*3*')
     {
          $AppInfo.Add($App.Name, $App.ApplicationSettings["FUNCTIONS_EXTENSION_VERSION"])
     }
}

$AppInfo

If this returns no apps, there is no currently discoverable Function App in that subscription targeting v3 by that method.

The available context does not confirm whether the email was sent in error. It only supports verifying whether any function apps in the subscription are still using older runtime versions.