OnePlus is now rolling out stable Android 10 updates for the OnePlus 5 and the OnePlus 5T. Both the OnePlus 5 and the OnePlus 5T were launched in 2017 and were slated to get Android 10 in Q2 of 2020.

source https://gadgets.ndtv.com/mobiles/news/oneplus-5-5t-oxygenos-10-android-software-update-rollout-user-reports-2235367