OISRT was an online SRT hosted in 2021 on a custom NITG build. Technically the second, with Celestial Harbor being the first. It specifically ran as a double-elimination bracket tournament, allowing everyone to have a second chance to climb back up into the leaderboard. It uses some of the foundation of Celestial Harbor by rewriting the entire server code, now all residing on a SRTMAN namespace.

The event ran from December 18th-19th, 2021.

The following footage is from a decompiled build, modified to run offline on an existing NITG 4.9 install.

Fun little fact: bundled on this executable is the full, all diffs stepfile of Flashback, which was used to sync your steps before you went to play the actual songs.