Recently (05/Jun/25) There are changes done in function Get-RequestHeader and due to this we are getting issue in our Azure DevOps yaml pipeline.
Find below code in which failure is happening when invoking ConvertFrom-SecureString -
function Get-RequestHeader { $Version = (Get-Command -Name Get-AzAccessToken).Version $SynapseToken = Get-AzAccessToken -ResourceUrl 'https://dev.azuresynapse.net' if ($Version -ge '5.0.0') { $token = ConvertFrom-SecureString $SynapseToken.Token -AsPlainText
We are getting below error:

pipeline is installing PowerShell version AzurePowerShell (5.257.0). I believe this version is not supporting "AsPlainText" parameter for ConvertFrom-SecureString and hence it is failing