Latest KaiOS 4 user agents:

User Agent	Browser	Device
Mozilla/5.0 (Mobile; rv:120.0) Gecko/120.0 Firefox/120.0 KAIOS/4.0	Firefox Mobile 120	Unknown
Mozilla/5.0 (Mobile; rv:123.0) Gecko/123.0 Firefox/123.0 KAIOS/4.0	Firefox Mobile 123	Unknown