ASP .NET 4.5.2 is the version packaged with CAM and that it was validated against.
Unless you have a pressing need to upgrade to 4.6 we would recommend you stay with that version for now. This applies to the STS server only, the proxy server does not rely on .NET. CAM has not been validated against 4.6.1."
We plan to regression test against .NET 4.6 when we next issue a Hotfix or new release to CAM. (Currently 8.1.1)
Unfortunately there isn't a schedule for this yet so I can't give you fixed dates at this time.