>And it's also nice not to yank the old community in case your customers still >depend on it, even if you do also support the RFC version as an alias of that >one.
That seems to be the case. Also, possibly the use of WKC 65535:666 has not picked up much. We observe that out of a total of 264,557 unique {Prefix, AS Path, Community = Any:666} seen in a whole day's worth of BGP Updates from RIPE-RIS (July 15, 2021), only 21 are with 65535:666. See slide 12 here: https://datatracker.ietf.org/meeting/111/materials/slides-111-grow-bgp-regularextendedlarge-community-analysis-01 (presentation at the IETF 111 GROW meeting last week) Sriram