First of all, please be informed with beta and real version of application.
What's Beta?
Beta app - It is an app released to test with customers everywhere. It is not the whole app. But a part of it where it has all required features. To get its feedback they release 'beta' app . This method of testing the app is called 'beta testing' hence the name 'beta' app. This is the last part of testing.
After a feedback and few modifications what we get is an 'App.
In oxford dictionary beta is The version of a new product,especially computer software,that is almost ready for the publicto buy or use, but is given to afew customers to test first.
To become a tester, open up play store- search WhatsApp- scroll down and click on " I'M IN" as shown below.
After that if you are able to be a tester you it will look like this:

Then you will get an update on WhatsApp. Update it. You have done it successfully.
