Board Thread:News and Announcements/@comment-9091559-20170114052811/@comment-26131865-20170115171035

"It was added since 5.6.0 of Nyanko Thing, released on 05/26/2016" for example. You need to know the exact release date, and for very old ones (like the release of Pogo Cat), it's hard to keep track of that (the date will likely be lost with time)