Visual Upgrade All SharePoint Sites in a web application using PowerShell

After the Migration using database attachment method, Had to upgrade all sites to New SharePoint 2010 User Interface. Used this PowerShell code to accomplish.

SharePoint 2010 visual upgrade powershell script

##### Visual Upgrade All SharePoint Sites to 2010 version in a Web Application #####
 
$SPwebApp = Get-SPWebApplication "http://migration.company.com"
 
    foreach ($SPsite in $SPwebApp.Sites)
    {
       foreach($SPweb in $SPsite.AllWebs)
        {
         
           $SPweb.UIVersion = 4  #set it to 3 if you want SharePoint 2007 look and feel
       $SPweb.Update()
    write-host $spweb.url
        }
    }
read-host  #just to pause

Or you can use the SPSite's VisualUpgradeWebs() method:

$webapp = Get-SPWebApplication <web-app-URL>
foreach ($site in $webapp.sites)
{
   $site.VisualUpgradeWebs() 
}

Here is the Before/After images: