A new issue surrounding the OnePlus 5T and its predecessor was recently brought to light by a customer who took to the official OnePlus forums to reveal that the company's latest flagship lacks the Widevine L1 Certification required to stream videos in HD and higher quality from DRM-protected platforms including Netflix, Google Play Movies, and Amazon Prime. The device still supports video streaming through these platforms but only in SD quality, as provided by the existing Widevine L3 Certificate.
As far as technical specifications are concerned, it's evident that the OnePlus 5T should be powerful enough to support video streaming in higher than SD quality, as the device is backed by the Qualcomm Snapdragon 835 chipset paired with 6GB or 8GB of RAM. And indeed, HD video streaming is still possible on non-DRM-protected platforms such as YouTube, where some OnePlus 5T owners report that 1080p video playback is available, though only if the option has been manually selected. Having said that, the problem stems from the lack of a certificate rather than hardware limitations, and as of this writing, it's not clear why OnePlus omitted this detail or whether it will provide a Level 1 certificate at a later date. According to a recent report citing an unnamed OnePlus spokesperson, support for Widevine L1 will be added through a firmware update at an unspecified later date, however no public statement on the matter can be found as of this writing so only time will tell whether the OEM will indeed address the issue later down the OnePlus 5T's lifespan.
The problem doesn't seem to be limited to the newly introduced OnePlus 5T but appears to affect the OnePlus 5 as well. Both smartphones were released in 2017 and share many hardware similarities across the board, including the Qualcomm Snapdragon 835 with its Adreno 540 graphics chip and the same RAM and on-board storage configurations. The main difference lies in the display, as the earlier model uses a 5.5-inch Optic AMOLED panel with a more conventional 16:9 aspect ratio, whereas the later variant employs a larger 6.01-inch panel with an 18:9 aspect ratio and a pixel count of 2,160 by 1,080.