OnePlus offers in-depth details on OxygenOS beta program
Basically, these community builds for OnePlus' OxygenOS are parts of the company's new, expanded software beta program. Their purpose is to involve the community in the development of OxygenOS. Also, this is a good way to test every feature, tweak, and addition to the OxygenOS.
According to OnePlus, this expanded software program consists of three tiers: Closed Beta, Open Beta, and Official Release. As might have guessed, there are very few OnePlus users in the closed beta “stream,” so if you're not part of it already, there's little to no chance to be part of this tier unless you're very lucky.
The open beta is available to all OnePlus users who want to install OxygenOS test builds on their phones. As the name suggests, the official release is meant for all compatible OnePlus smartphones and are supposed to be bug-free.
OnePlus announced that it will provide around 4 OxygenOS community build updates for closed beta per month, 2 builds per month for open beta, and 1 update every 1-2 months for the official release “stream.”
All closed beta releases are referred to as “alpha builds” since they aren't stable at all and they lack the polish of an official release. OnePlus will deliver more OxygenOS updates for the closed beta “stream” since new features are added all the time.
The open beta builds are all about fine-tuning and make the software as stable as possible by fixing and bugs found during tests. These are usually semi-public, which means that everyone can try them out.
And now you know why it takes up to 2 months to release an OxygenOS update for the general public. These updates are first tested within the community, and then offered to the OnePlus users.