OnePlus 3 and OnePlus 3T are all set to get the Android P software update once the final version launches later this year. Chinese phone maker OnePlus has been on the front foot in terms of latest major Android updates and regular security patches, whether be it for the latest OnePlus 6, last year's OnePlus 5, OnePlus 5T, or even the OnePlus 3 and OnePlus 3T from 2016. Notably, the 2016 OnePlus models were launched with Android 6.0 Marshmallow and this will be the third major update for them, a rare occurrence in Android smartphone life cycles.
Back in June this year, OnePlus had announced that it would be pushing a minimum of two years of software updates and three years of security updates on its current lineup of smartphones, as part of the new Software Maintenance Schedule.
"Android P update will be available on the OnePlus 6, OnePlus 5/T and OnePlus 3/3T, in this order," states Gary C, Staff Member, OxygenOS Operations, OnePlus. So, if we assume that the final Android P release to AOSP and ecosystem arrives in Q3 2018, the stable update to OnePlus' 2016 flagships probably won't be released until the first few months of 2019. However, the decision of upgrading these phones to the latest software is a welcome decision nonetheless.
Adding to that, the OnePlus forum post states that the two smartphones will not receive Android 8.1 Oreo, and will instead be upgraded to Android 9.0 straight from Android 8.0. This development comes after "internal discussions and evaluation".
Just recently, as part of the latest OxygenOS 5.0.4 update on the two phones, the company's representative announced that this will not be their last stable OxygenOS version. This update brought the latest July security patch, and bug fixes to the native camera app and third-party camera apps on WhatsApp and Snapchat. Face Unlock capabilities were brought to the two phones back in May this year with the OxygenOS 5.0.3.