This is a stable update, and it is marked as OxygenOS 10.0.4 for the OnePlus 7 and 7 Pro. In the case of the OnePlus 7T Pro, the update carries the OxygenOS 10.0.7 mark. Those build numbers are different for Indian users.
Interestingly enough, changes are the same for all three phones. OnePlus published the exact same changelogs for all three devices.
Optimized RAM management is the most notable change in this update for the OnePlus 7, 7 Pro & 7T Pro
The first item in the changelog is the optimized RAM management for the OnePlus 7, 7 Pro, and 7T Pro. Those three phones did not have any significant issues with RAM management, but users have been complaining about the phone's ability to keep processes active in the background. So, perhaps OnePlus took care of that here, made its UI a bit less aggressive.
On top of that, this update brings improvements to black/blank screen issues when it comes to some applications. We've experienced this with Nova Launcher on the OnePlus 7 Pro, so we're glad it's fixed.
OnePlus has also added a feature to support reminders for privacy alerts. This update also brings an Android security patch for January 2020 to all three phones.
As far as system changes are concerned, this update also improves system stability, and fixes a number of smaller bugs that the company found.
All other changes that are listed in this changelog are India-related. They have to do with the networks, cloud service, work-life balance, and cricket scores. If you're interested in any of that, and are from India, links are in the first paragraph.
This is a staged rollout, keep that in mind
Do note that this is a staged rollout, as it's usually the case with OnePlus' update. That means that this update will not become available straight away to all of you.
A small number of users will be able to download it right now, while OnePlus will push it out to everyone else in a couple of days, if everything goes according to plan.
If the company spots some issues with this update, it may opt to halt the rollout. In that case, you'll have to wait for the company to fix those issues, and start rolling the update again. Let's hope that won't happen, though.
It is also worth noting that OnePlus removed one-handed mode from its recent Open Beta update. That is a rather odd move by the company, as that feature was expected to arrive to the stable channel soon.