I have a custom webpart which worked in SP 2007 but after the migration to 2013 it failed to work properly. There was no visual display. The custom webpart is very old and the source code is no longer available for it.
Any ideas on what I can do? I'm trying to avoid rewriting it. It does not use any third party controls. Just straight custom code.
I used reflector and the only issue is that it uses v12 of the SharePoint.dll.
Is there any way around this without redeveloping?