If you have a look at the codebase of version 2.0 here: https://github.com/thoughtbot/high_voltage/tree/11e38c643ff8b5ea1c6e04999034a8d5bcb4f711
There is no such version implemented in the gem.
It was added just recently: https://github.com/thoughtbot/high_voltage/commit/1668e54be41dd50f6c36ac6ab6d46069ffd0d636