Android Police was the first to spot the WhatsApp beta-testing program, noting that WhatsApp has been providing updates of its app via its own site, but users had to agree to allow their devices to permit installations “from untrusted sources,” because those updates weren’t coming via Google Play.
Rita El Khoury of Android Police added:
It does make more sense to have an official Play Store beta program. Updates get delivered automatically, they’re incremental so you don’t have to download the entire APK (Android application package) each time (that matters when you’re on a limited connection and WhatsApp releases a new bug fix every couple of hours), and you don’t have to change the untrusted sources setting if that’s something you’re paranoid about.
She pointed out that interested users are not required to join Google+ communities or Google Groups, and that those who choose to join the program will begin automatically receiving updated, unreleased versions of WhatsApp on their devices.
WhatsApp Inc. has invited you to a testing program for an unreleased version of the WhatsApp Messenger app.
As a tester, you’ll receive an update that includes a testing version of the WhatsApp Messenger app. Please note that testing versions may be unstable or have a few bugs.
Send your feedback to WhatsApp Inc. using the contact information: firstname.lastname@example.org.
WhatsApp Android users: Are you interested in beta-testing the app?