Powershell Script to Validate on Whether Custom Feature Requires Upgrade

$LogTime = Get-Date -Format yyyy-MM-dd_hh-mm
$LogFile = ".\ValidateFeatureNeedsUpgradePatch-$LogTime.rtf"

# Add SharePoint PowerShell Snapin


if ( (Get-PSSnapin -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue) -eq $null ) {
    Add-PSSnapin Microsoft.SharePoint.Powershell
}

$scriptBase = split-path $SCRIPT:MyInvocation.MyCommand.Path -parent
Set-Location $scriptBase


#Deleting any .rtf files in the scriptbase location
$FindRTFFile = Get-ChildItem $scriptBase\*.* -include *.rtf
if($FindRTFFile)
{
  foreach($file in $FindRTFFile)
  {
   remove-item $file
  }
}


start-transcript $logfile

$featureName = ""

[string]$featureName = Read-Host "Enter the Feature name [e.g. MyCustomFeature]"


try {

   Write-Verbose "Query for features requiring upgrading ..."

   $fd = Get-SPFeature $featureName

   switch ($fd.Scope) {
      "Farm" {
         $output = [Microsoft.SharePoint.Administration.SPWebService]::AdministrationService.QueryFeatures($fd.Id, $true)
         break
      }
      "WebApplication" {
         $output = [Microsoft.SharePoint.Administration.SPWebService]::QueryFeaturesInAllWebServices($fd.Id, $true)
         break
      }
      "Site" {
         $output = foreach ($webapp in Get-SPWebApplication) {
         $webapp.QueryFeatures($fd.Id, $true)
      }
      break
   }
   "Web" {
      $output = foreach ($site in Get-SPSite -Limit All) {
      $site.QueryFeatures($fd.Id, $true)
   }
   break
   }
}
Write-Output $output

}
catch [Exception] {
   Write-Error $Error[0]
   $err = $_.Exception
   while ( $err.InnerException ) {
      $err = $err.InnerException
      Write-Output $err.Message
   }
}