Pokémon GO announced their newest update and patch notes via Twitter this weekend. After a lot of distress by many fans who did not see this update even 48 hours after this update announcement, we can finally confirm that this Buddy update has been rolled out to all users today.
Unfortunately this update does not contain a working PokéTracker. What it does contain is the option to select one of your captured Pokémons to be your buddy. What this means in practice is that you can take your selected Pokémon for a walk and earn that Pokémons candy after having walked a certain distance. If you're curious to see how this looks like with a trusted Pikachu by your side, take a look at the screenshots included below.
Even though you are limited to one Pokémon as your buddy at the time, you are free to swap which Pokémon you'd prefer to be your buddy at any time.
It is also worth noting that this update fixes a few bugs and includes support for the highly anticipated and long delayed Pokémon GO Plus device, which is due to release on September 16th. The patch notes also explain that Niantic is still working on eliminating bots and scrapers from the game, and as such the app will no longer be supported for rooted or jailbroken devices.