From the Release Notes for 8.6.1 – New Features:
We introduced support for the ASA 5512-X, ASA 5515-X, ASA 5525-X, ASA 5545-X, and ASA 5555-X.
Looks like the entire ASA family got replaced excepting the ASA 5585-X. I’m guessing this is related to the ASA CX announcement last week at the RSA conference.
Updated: Yes, here is the announcement that it’s ASA-CX Related
Can’t find any other meaningful data about performance and features though. I’m guessing this was a “real soon now” announcement where everything “works in Powerpoint”1
as Ivan Pepelnjak says. ↩