OnePlus 5 confirmed to be discontinued once it's sold out
However, the OnePlus 5T is not a major upgrade over the OnePlus 5. With the exception of the display and camera, these phones are almost the same. That's what makes OnePlus' decision to phase out the OnePlus 5 perfectly justifiable.
If you look at our previous phone, the OnePlus 3T the last batch was sold out during Diwali and now the product will be discontinued. The same goes for the OnePlus 5, which will also be sold out in sometime, and we’ll have only one product OnePlus 5T in the market. As a brand we want to make sure there is one device which is the latest, and the previous devices are usually sold out once the new product launches.
Mr. Aggarwal also said that OnePlus launched a second flagship with minimal improvements over the previous model because at the time of OnePlus 5's release it was the best phone the company could possibly offer.
However, in the meantime, many companies launched new smartphones that offer similar, if not better specs, so OnePlus needed to remain competitive, hence the OnePlus 5T's release.
source: The Indian Express
Things that are NOT allowed: