The new OxygenOS 3.2.1 update includes all the improvements included in the previous 3.2.0 update, like the sRGB mode (offers more accurate color reproduction) in developer options, improved RAM management (bring faster loading of apps and games), fix for SIM recognition issue, better GPS performance, etc. as well as additional improvements and fixes.
Below are some of the highlights of OxygenOS 3.2.1 update for OnePlus 3 This is an incremental update and you do not need to update to the previous OxygenOS 3.2.0 to get the new update. As always, the OTA update is rolled out in phases, so it will take few days to reach the update on all devices. If you have not received the OTA update notification on your device, you can manually check it by going to phone Settings > About phone. Manual Installation of OxygenOS 3.2.1 If you are prefer manual installation, then you can download and sideload the ROM zip file via adb. If you have already updated to OxygenOS 3.2.0, just download the OTA file [HERE] (15MB) and install it. If you have not installed the 3.2.0, then download the full ROM [HERE] (1.2GB) and sideload it via ADB. You may follow the flashing instruction as given here (source)
