You can now sign up to be a tester for Sumerians before the Early Access release:
Fill in form to become a tester for Sumerians.
This testing period is from the 5th to the 14th of October, 2020.
New beta from the 11th to the 16th of November, 2020.
Depending of the number of applications not everyone may be selected.
This test is only for Windows users. Mac and Linux versions are expected to be added during the Early Access.