Vulnerability in EPiServer.Forms
Is it possible to run CMS 7 and CMS 5 on the same webserver (different sites) and is this supported ? Any problems with .Net code, scheduler, etc ?
Would not recommend trying it, the system requirements are quite different and the forward/backwards compatibility issues (IIS, .NET versions, Windows Server versions) will give you nightmares.
Compare CMS 5 sys reqs VS CMS 7 sys reqs.