Found this thread accidentally, and thought reviving it with new data and summary may be a good idea.
- online-go.com was started on Nov. 17, 2005
- nova.gs was started in Feb. 2013, merged with OGS on Oct. 19, 2013
- OGS version 4.0 released in early 2014, 4.2 in Dec. 2014
- OGS version 5.0 released on Feb. 13, 2017
v.5.0 structure
nginx+uwsgi+django for the app server
node for the real time game and chat server
redis+postgres for application database
Cloudflair CDN as a new feature - Migration of database to Cassandra completed in 2017
- OGS user interface became open source on Feb. 25, 2017
- Glicko2 rating system introduced on Aug. 8, 2017
- Migration from Elo to Glicko2 rating completed in 2017