ASyncOS 9.5 is in Limited Deployment at the moment but you don’t have to wait long before it hits an ESA near you as Cisco seem to be pushing out ASyncOS releases pretty quickly these days.
9.5 comes with a bunch of new features including one many people have been waiting for – support for TLS 1.2.
See the release notes @ http://www.cisco.com/c/dam/en/us/td/docs/security/esa/esa9-5/ESA_9-5_Release_Notes.pdf
If you don’t want to wait for it to hit the General Deployment phase then you can raise a TAC support request with the serial number of your appliance and a request to be put on the LD list for release 9.5.
I’ll probably be doing this my self in the next few days. I also have a virtual appliance so can always snapshot the VM before the upgrade and roll back in case anything goes awry.