Historically, WhatsApp never released an official .cab file for Windows Mobile 6.1 (standard or professional). The app required Windows Mobile 6.5 or a specific patch to run the Java emulator version. This draft reflects that technical reality. Title: WhatsApp Messenger .cab for HTC Windows Mobile 6.1 Applies to: HTC Touch Pro, HTC Diamond, HTC HD2 (running unofficial 6.1 ROMs), HTC Touch Dual, HTC S740