Always-on displays have become a thing recently, with the general idea being that you don't need to use power waking up your phone from a low-power state just to be able to use it as a clock. Obviously keeping the display on will itself use up a chunk of the phone's power, and that seems to be part of the reason OnePlus pulled the feature from its latest handset after a recent update.
Most of you will remember that the OnePlus 6 has an OLED screen, which has the advantage of being able to selectively power areas of the screen that aren't black. That naturally saves battery, and means having an always-on display isn't the same as keeping the phone switched on all day. Still there have been some concerns with the OnePlus 6, to the point where the company used the Day One update to remove that particular feature.
This was spotted by users who went exploring the features before updating their phone, and while an official statement has yet to be released by the company OnePlus customer support told Reddit user Cell_7 that it was thanks to "battery concerns". Nothing was clarified beyond that, but it seems likely there must be some sort of glitch that causes excessive battery drain. Other companies have been using always-on displays for years and faced few, if any, issues.
It's strange that it would be pulled like that, but a lot of things changed on the OnePlus 6 between the time the phone was built and launch. In my review I noted that it wasn't a Google certified device right out of the box, and remained that way until its first update. Similarly the notch-hiding feature was greyed out until that same update rolled out. Perhaps OnePlus decided it didn't want that feature in the first place, or maybe it really was problematic. Until we get a full statement, we'll never know. [Slashgear]