v1.3.0-rc.2

Download it from here:
https://github.com/gustavo-iniguez-goya/opensnitch/releases/tag/v1.3.0-rc.2

Despite of being tagged as "pre-release", it's fairly stable. We'll release v1.3.0 soon.

v1.2.0

See this for more details:
https://github.com/gustavo-iniguez-goya/opensnitch/releases/tag/v1.2.0

Don't forget to read the instructions (installation from command line preferable):
https://github.com/gustavo-iniguez-goya/opensnitch/wiki/Installation

And if you find any problem, take a look at the common problems