Essential is wasting no time bringing the latest Android Oreo build to its users. The latest update with build no. OPM1.180104.141 brings the latest Oreo 8.1 version. This comes with April security patches, which the Pixel got a few days ago; support for Bluetooth 5.0, which is more an update on the software side as the hardware has supported the feature since launch; modem stability and other bug fixes; performance improvements; and “proper handling” of external game controllers.
Source: Android Police