0.6.0 will be released next week and because of that we are putting out a test build of the new version.
To play the test build switch to the "beta" version in the game properties in the Steam client. Note before you download that the day/night cycle needs to be turned on in advanced new game settings to work. All the other major features like Thriveopedia will work with existing saves in a limited manner. And please note that for now the new launcher 2.0 doesn't yet start in seamless mode on Windows (so you'll still see the launcher before playing Thrive). This will be fixed for the full 0.6.0 release.
If you have any feedback please post it on the relevant thread on our forums at: https://community.revolutionarygamesstudio.com/t/0-6-0-release-candidate-testing-and-launcher-2-0-testing/5735 or in the comments below.