How can I get the early beta version?

I often read that you guys use some beta versions with the new features already?

How do I install early beta versions?

Beta tests only work on the Ipad.
You need an invitation from the developer, you can apply for it.
Then you can test the beta via the app Testflight.
I think there are only a limited number of test slots.
Otherwise you can use the web demo, which is almost always up to date.