Only a few days before the release of the OnePlus 5T with Nougat onboard, the OnePlus 3 and 3T flagships receive their last major software update. This Android Oreo-based update for them comes as OxygenOS 5.0.
https://www.notebookcheck.net/OnePlus-3-and-3T-receive-Android-Oreo.264184.0.html
In case anyone is wondering, the update for my 3T (in Norway) arrived today. Much faster rollout than the previous major update, which took several weeks to arrive (had to use a German VPN to get it in the end!).