The Motorola Moto G5 was released in March of 2017 and is still stuck on Android 7.1 Nougat, despite using a mostly stock-looking Android build. No reports have surfaced of yet of a working update for the Moto G5 but Motorola has confirmed the Moto G5 family will get Oreo, eventually. Well the wait is finally coming to an end - a new report card in Geekbench's database shows a Moto G5, model name XT1670, running Android 8.1. This means that the update is already in testing and if all goes smoothly it should be released soon for the Moto G5. No word yet on the Moto G5s and Plus, but...
Source: https://www.gsmarena.com/motorola_moto_g5_spotted_flaunting_android_81_on_geekbench-news-31205.php