Find & Fix Outdated Azure Function Apps

Useful Scripts to Keep Track of Updates

If you’re managing Function Apps across multiple environments, you probably already know how easy it is to lose track of runtime versions.

One outdated runtime, and suddenly you're dealing with broken flows, unsupported features or worse, security issues.

Microsoft sends the following alerts, well, ahead of this expiry time:

• Azure Portal notifications

• Emails to subscription owners

• Warnings in client tools and Azure Portal UI when an app is running on a version that is either retired, or about to be retired in the next 6 months

• Official Azure Functions Supported Languages document

This might not be proactive enough in your setups spanning multiple subscriptions.

This is where these CLI scripts might help to:

✅ Scan across subscriptions

✅ Identify apps on outdated runtimes/language versions

✅ Stay compliant and secure with minimal effort

• List all Windows-based Function Apps:

az functionapp list --query '[?contains(kind, `functionapp`) && !contains(kind, `linux`)].{Name:name, ResourceGroup:resourceGroup, OS:`Windows`}' --output table

• List Windows-based Function Apps with their language stack versions:

az functionapp list --query "[? !contains(kind, 'linux')].{name:name, resourceGroup:resourceGroup}" -o json | ConvertFrom-Json | ForEach-Object {
  $appSettings = az functionapp config appsettings list `

        -n $_.name -g $_.resourceGroup `

        --query "[?name=='FUNCTIONS_WORKER_RUNTIME' || name=='WEBSITE_NODE_DEFAULT_VERSION']" -o json | ConvertFrom-Json

    $siteConfig = az functionapp config show `

        -n $_.name -g $_.resourceGroup `

        --query "{powerShellVersion: powerShellVersion, netFrameworkVersion: netFrameworkVersion, javaVersion: javaVersion}" -o json | ConvertFrom-Json

    $runtime = ($appSettings | Where-Object { $_.name -eq 'FUNCTIONS_WORKER_RUNTIME' }).value

    $version = switch ($runtime) {

        'node'      { ($appSettings | Where-Object { $_.name -eq 'WEBSITE_NODE_DEFAULT_VERSION' }).value }

        'powershell'{ $siteConfig.powerShellVersion }

        'dotnet'    { $siteConfig.netFrameworkVersion }

        'java'      { $siteConfig.javaVersion }

        default     { 'Unknown' }

    }

    [PSCustomObject]@{

        Name          = $_.name

        ResourceGroup = $_.resourceGroup

        OS            = 'Windows'

        Runtime       = $runtime

        Version       = $version

    }

} | Format-Table -AutoSize

• List Windows-based Function Apps running on unsupported language runtimes: (as of April 2025):

az functionapp list --query "[? !contains(kind, 'linux')].{name: name, resourceGroup: resourceGroup}" -o json | ConvertFrom-Json | ForEach-Object {

    $appSettings = az functionapp config appsettings list -n $_.name -g $_.resourceGroup `
        --query "[?name=='FUNCTIONS_WORKER_RUNTIME' || name=='WEBSITE_NODE_DEFAULT_VERSION']" -o json | ConvertFrom-Json

    $siteConfig = az functionapp config show -n $_.name -g $_.resourceGroup `
        --query "{powerShellVersion: powerShellVersion, netFrameworkVersion: netFrameworkVersion}" -o json | ConvertFrom-Json

    $runtime = ($appSettings | Where-Object { $_.name -eq 'FUNCTIONS_WORKER_RUNTIME' }).value

    $version = switch ($runtime) {
        'node' {
            $nodeVer = ($appSettings | Where-Object { $_.name -eq 'WEBSITE_NODE_DEFAULT_VERSION' }).value
            if ([string]::IsNullOrEmpty($nodeVer)) { 'Unknown' } else { $nodeVer }
        }
        'powershell' { $siteConfig.powerShellVersion }
        'dotnet'     { $siteConfig.netFrameworkVersion }
        default      { 'Unknown' }
    }

    $isUnsupported = switch ($runtime) {
        'node' {
            $ver = $version -replace '~', ''
            [double]$ver -le 16
        }
        'powershell' {
            $ver = $version -replace '~', ''
            [double]$ver -le 7.2
        }
        'dotnet' {
            $ver = $siteConfig.netFrameworkVersion
            $ver -notlike 'v7*' -and $ver -notlike 'v8*'
        }
        default { $false }
    }

    if ($isUnsupported) {
        [PSCustomObject]@{
            Name          = $_.name
            ResourceGroup = $_.resourceGroup
            OS            = 'Windows'
            Runtime       = $runtime
            Version       = $version
        }
    }

} | Format-Table -AutoSize

If result empty, this means: all your Windows-based Azure Function Apps are running supported versions of: Node.js, PowerShell or .NET.

• List Windows Function Apps running on a specific language version (Example: Node.js 18):

  az functionapp list --query "[?!contains(kind, 'linux')].{name: name, resourceGroup: resourceGroup}" -o json |
  ConvertFrom-Json | ForEach-Object {
  
      $appSettings = az functionapp config appsettings list `
          -n $_.name `
          -g $_.resourceGroup `
          --query "[?name=='FUNCTIONS_WORKER_RUNTIME' || name=='WEBSITE_NODE_DEFAULT_VERSION']" `
          -o json | ConvertFrom-Json
  
      $runtime = ($appSettings | Where-Object { $_.name -eq 'FUNCTIONS_WORKER_RUNTIME' }).value
      $nodeVersion = ($appSettings | Where-Object { $_.name -eq 'WEBSITE_NODE_DEFAULT_VERSION' }).value
  
      if ($runtime -eq 'node' -and $nodeVersion -eq '~18') {
          [PSCustomObject]@{
              Name           = $_.name
              ResourceGroup  = $_.resourceGroup
              OS             = 'Windows'
              Runtime        = $runtime
              Version        = $nodeVersion
          }
      }
  
  } | Format-Table -AutoSize
  

• List Windows Function Apps running on Node.js runtime:

az functionapp list `
  --query "[?!contains(kind, 'linux')].{name: name, resourceGroup: resourceGroup}" `
  -o json | ConvertFrom-Json | ForEach-Object {

    $appSettings = az functionapp config appsettings list `
      -n $_.name `
      -g $_.resourceGroup `
      --query "[?name=='FUNCTIONS_WORKER_RUNTIME' || name=='WEBSITE_NODE_DEFAULT_VERSION']" `
      -o json | ConvertFrom-Json

    $runtime = ($appSettings | Where-Object { $_.name -eq 'FUNCTIONS_WORKER_RUNTIME' }).value

    if ($runtime -eq 'node') {
        $version = ($appSettings | Where-Object { $_.name -eq 'WEBSITE_NODE_DEFAULT_VERSION' }).value

        [PSCustomObject]@{
            Name          = $_.name
            ResourceGroup = $_.resourceGroup
            OS            = 'Windows'
            Runtime       = $runtime
            Version       = $version
        }
    }
} | Format-Table -AutoSize

• List Linux* Function Apps with their language stack versions.

az functionapp list \
  --query "[?siteConfig.linuxFxVersion!=null && siteConfig.linuxFxVersion!=''].{
    Name: name,
    ResourceGroup: resourceGroup,
    OS: 'Linux',
    LinuxFxVersion: siteConfig.linuxFxVersion
  }" \
  --output table

• Linux* Function Apps on a specific language stack version (Ex: Node.js 18):

az functionapp list \
  --query "[?siteConfig.linuxFxVersion=='Node|18'].{
    Name: name,
    ResourceGroup: resourceGroup,
    OS: 'Linux',
    LinuxFxVersion: siteConfig.linuxFxVersion
  }" \
  --output table

*Running on Elastic Premium and App Service Plans

With just a few Azure CLI commands and PowerShell scripts, you can quickly identify outdated runtimes, prioritize upgrades, and stay ahead of upcoming retirements.

That’s all for today, see you in the next one.