T-mobile sells a KaiOS phone, the Alcatel Go Flip, that my mom reports works well. Her old phone was gsm only, and was starting to have coverage issues (because of band reprovisioning) and then died.
It has a menu item for updates, but claims to be running KaiOS 1.0 and doesn't have any updates available (wikipedia says 2.5 is the latest); so that's not super promising.
It has a menu item for updates, but claims to be running KaiOS 1.0 and doesn't have any updates available (wikipedia says 2.5 is the latest); so that's not super promising.