This release includes the newly released duels feature that allows you to duel your friends in real-time.
To use the new feature, just set the backend service (ShellTimer.WebApi) URL using the new config command, then create a new duel using the duel command, or join an existing duel using the -j flag on the duel command. Duels support all the same configuration features you're used to on the timer.
To use the application download and extract the zip archive corresponding to your OS and architecture and run the executable from the terminal (I recommend powershell on windows).
Note: If you are worried about the files being relatively large, it's only because they were published with the .NET runtime bundled into the executable. This was done to allow anyone to run the application regardless of .NET being installed.