The final Windows Mobile version was (around 2016). This version worked on WM 6.1 but lacked later features like voice calling, end-to-end encryption (added later on other platforms), and stickers.
The most "interesting" aspect of for Windows Mobile 6.1 today is its status as a historical artifact; the official service for all Windows Mobile platforms permanently ended on December 31, 2019 . Because WhatsApp requires a server-side handshake and verification code to function, the original .cab files can no longer register new accounts or send/receive messages on modern servers. Key Context for Legacy HTC Users whatsapp messenger.cab for htc windows mobile 6.1
In the past, users would look for these specific files for their HTC devices (like the HTC Touch Pro, HD, or Diamond): The final Windows Mobile version was (around 2016)