I was working on the migration from SharePoint 2010 to
SharePoint 2013. I have detached and attached the SP content database (classic
mode authentication) from SharePoint 2010 server to 2013 server. I have also
mounted the SharePoint content DB (classic mode authentication) to 2013 classic
mode web application. Next step is to convert SharePoint 2010 classic-mode web application to a SharePoint 2013
claims-based authentication. In this blog you will see how to convert SharePoint 2010 classic-mode web application
to a SharePoint 2013 claims-based authentication using PowerShell.
Convert-SPWebApplication -Identity http://C4968397007:20130 -To Claims -RetainPermissions -Force
Note: Make sure you have required memberships to perform this activity.