Official notice from the anime site.
"Haikyuu!! Final" will be a 2-part movie production, which will be the sequel to the anime. The official website has added a "Movie" section in which the official PV is played.
It is set to be released in Aug 2023.
#ハイキュー_Vリーグ
I hate to break it to you all, but this isn’t a confirmation at all. The tone used here is speculative, as in “the cafe’s theme will reflect what we expect for the possible S5” kind of thing. It’s more so to promote the collaboration than anything else.