I had already reported on the Sophos UTM Firewall, which is even free for private use. Unfortunately, there was the limitation that the Web Application Firewall did not provide Outlook Anywhere support.
However, since Forefront TMG has now been discontinued, other manufacturers also seem to be jumping on the bandwagon and integrating Outlook Anywhere support into their products. Sophos also offers support for Outlook Anywhere (RPCoverHTTPS) in a beta version of its UTM firewall. It will probably not be long before the beta becomes a stable release. Personally, I am of course very happy about this, then I can save my TMG server 
Here is the link for all those who use a UTM:
I haven't tested it yet, but I still have time until it is stable. Incidentally, KEMP will also be upgrading its load balancers with the ESP:
http://www.kemptechnologies.com/de/tmg-edge-security-authentication.html
I suspect there will be more to come in the near future. If you would like, please feel free to post solutions in the comments that offer similar support to TMG for Exchange. Maybe we can create a list of compatible products.