You are downloading the WhatsApp XAP file v2.18.368.0 for Windows Phone. WhatsApp is a free and useful Social app: WhatsApp will no longer be supported on Windows Phone after December 31, 2019.You can continue using WhatsApp on Android, iOS or KaiOS ... You can now download the offline XAP file to install & try it.
Download Locations for WhatsApp 2.18.368.0 XAP file
Important Notice: Now Due To Unspecified Limitations, You Can Not Use The Offline XAP File To Install It Any More.
To try to install it manually from an SD card, you should choose one of the server location above to get the offline WhatsApp XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.