RemoveOutOfDatePasswords.ps1

Write-Information "Remove all KeyCredential started before $(Get-Date $dtStart -Format 'O' )..."
$serviceprincipal = Get-AzureADServicePrincipal -All:$true -Filter "DisplayName eq '$SharePointAddInName'" 
$serviceprincipal.KeyCredentials | ForEach-Object{
    $credential = $PSItem
    if($($credential.StartDate) -lt $dtStart)
    {
        Write-Information -MessageData:"Removing KeyCredential $($credential.KeyId)"
        Remove-AzureADServicePrincipalKeyCredential -ObjectId:$serviceprincipal.ObjectId -KeyId:$credential.KeyId
    }
}

Write-Information "Remove all PasswordCredential started before $(Get-Date $dtStart -Format 'O' )..."
$serviceprincipal.PasswordCredentials | ForEach-Object{
    $credential = $PSItem
    if($($credential.StartDate) -lt $dtStart)
    {
        Write-Information -MessageData:"Removing PasswordCredential $($credential.KeyId)"
        Remove-AzureADServicePrincipalPasswordCredential -ObjectId:$serviceprincipal.ObjectId -KeyId:$credential.KeyId
    }
}