OnePlus has just announced that a new beta update has started rolling out to the OnePlus 3 and OnePlus 3T handsets. The OxygenOS Open Beta 27 is coming to the OnePlus 3, while the Open Beta 18 is aimed for the OnePlus 3T units. These two updates are differently marked, but they bring the very same features / improvements. Do keep in mind that you won't be able to see or install this update if you're running a stable version of OxygenOS, only if you're a part of OnePlus' beta program and are running a beta version of the software.
Now, as far as changes are concerned, OnePlus has included a new Do Not Disturb (DnD) UI here, and the company says that the DnD part of the settings is now much easier to understand thanks to the changes the company made. In addition to that, OnePlus has optimized standby battery usage on the two devices, and has also introduced some improvements to 'Smart Text Selection', though the company does not state what kind of improvements, it only says 'this option should now work as intended'. General performance updates are also a part of this update, and so is Google's Android security patch for October 2017. On top of all that, OnePlus has updated its own apps on the OnePlus 3 and 3T, while GMS applications have also been updated. To be more specific, the OnePlus Gallery got an update, and some bugs have been squashed in Weather, Recorder and File Manager applications. As the last entry in the changelog, OnePlus listed 'Other bug fixes and optimizations', and that includes updates to language localization, fixes for the 'extended screenshot' option in some apps, Bluetooth improvements, camera gesture fixes and some memory optimizations.
As you probably already know, OnePlus announced the OnePlus 5T yesterday, a successor to the OnePlus 5 which was announced earlier this year. The OnePlus 3 and 3T were both announced last year, and are still very much current smartphones. Unlike the OnePlus 5 and OnePlus 5T, the OnePlus 3 and OnePlus 3T sport the very same design, while both devices are fueled by the Snapdragon 821, and they both come with 6GB of RAM on the inside. The OnePlus 3 and 3T sport a 5.5-inch fullHD (1920 x 1080) Optic AMOLED display, while a 16-megapixel shooter is placed on the back of both of these phones.