Never was officially supported. SmartThings doesn’t want button devices that can only support one protocol.
The Aeon minimote and four button keyfob work as multiprotocol devices and are officially supported.
The smartenIt 3 toggle and the securifi 3 button key fob (which only costs $15) aren’t officially supported, but work well using the same concept as the Minimote, so any button can control a mix of zigbee or Z wave or cloud service devices.