The Pokedex in Pokemon GO has remained nearly the same for quite some time with minor adjustments. Players would likely welcome something new for the Pokedex, and Pokeminers may have found what those new changes are.
For some time now, Pokeminers have been following the Pokedex updates in the Android version APK files. Every now and then, a new category gets added to the files, and now there is almost a full picture of what is to come. However, players should keep in mind that nothing is official until it comes from Niantic themselves.
Categories may be added to the Pokedex in a future update that expands the information within. As of now, the Pokedex shows which Pokemon the player has caught and when they tap on a given Pokemon, additional stats appear. Those include how many have been seen, caught, lucky, or purified.
With the categories update, the Pokedex will display far more detail such as shiny encounters, three-stars, four-stars, and even shiny-three stars. Each Pokemon in the Pokedex will have categories assigned that are similar to tags and they are unlocked as players make potential progress. Players will not be able to see them until they reach milestones on the category, which will be hidden from the UI.
What separates the new categories from the normal Pokemon GO Pokedex
Though there are only additional statistics being added to the Pokedex, it may be a bigger deal than it initially sounds.
For players that have been playing a long time, thousands of Pokemon have been caught, maybe kept for a long time, and released into the wild. If speculation is correct, the Pokedex will allow players to let go of Pokemon they don't need, and still track that they had them at one point in time.
A lot more was revealed in the datamine such as raid stadium visuals and quest branching, but players will need to wait for official announcements.