Cisco to support flow spec

Looks like 5.2.0 has been available since July.

http://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r5-2/general/release/notes/reln_520a9k.html
http://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k_r5-2/routing/configuration/guide/b_routing_cg52xasr9k/b_routing_cg52xasr9k_chapter_011.html

 7.3, last I heard..

Also, is this RFC 5575-compliant flowspec?

 yes, with some recent enhancements to the specs (v6 support, relaxed origin check, extra redirect options, and a few more)