The OnePlus One will receive the official Lineage OS 17.1 Android 10 update
The OnePlus One is one of the few phones that still has an active development community years after OEM software support ended. OnePlus released its first smartphone in 2014 running on a base of Android 4.4.2 KitKat, with software support ceasing as of Marshmallow 6.0.1. However, fans of OnePlus' original smartphone have kept it alive with years of additional third-party ROMs.
Lineage OS has also added official support for the OnePlus One on version 17.1 of its OS. Lineage OS 17.1 is based on Android 10 and started being issued to devices on April 1, 2020. The OnePlus One is yet to receive an official build of Lineage OS 17.1, although development remains active for the device. You can keep abreast of any changes by heading to the OnePlus One Lineage OS 17.1 Changelog.