There is a two-step process you need to follow to become a beta tester.
1. Join DigiCal Beta Group on Google+
To get access to the latest beta release for DigiCal, please join our Google+ Community "DigiCal Beta Group".
2. Sign up to become a beta tester
You can sign up by clicking this Google Play link. You'll now receive DigiCal updates from the Play Store whenever we push out a new Beta release (in addition to the regular releases).
3. To leave the beta test, select "Leave the test".
If you want to leave the beta testing group, it's not necessary to uninstall the beta version.
If you want to leave the beta channel, the best way is to select "leave the test", on this page, then wait until the next DigiCal update.
This is the update that is available to all users and once you move to that version you'll remain on the regular users track.
NOTE: Uninstalling DigiCal will cause you to lose your widget settings, app preferences, and any color changes you've made to your calendars or individual events via the DigiCal app that were not synced to your calendar server. (DigiCal 2-way color syncing only works with Google Calendar accounts, this means all other calendar accounts will lose their DigiCal color settings and go back to default.
For Google Calendar users please see the 2-way color syncing help page for the exact explanation of what is synced and what isn't).