Although it's hard to find due to its massive popularity, the Pokémon Go Plus accessory could use some work. It doesn't notify you of Pokémon you haven't seen before, and it can sometimes be difficult to catch more rare Pokémon you've already seen, since the device doesn't do a great job of distinguishing PokéStops from Pokémon, or Dragonites from Pidgeys.
The latest update to Pokémon Go doesn't fix all these issues, but it makes it easier to stratify what you're running around for. After this update, Pokémon Go Plus users will be able to specify whether they want to receive notifications for only Pokémon, PokéStops, or both. This means that if you're only interested in loading up on Pokéballs during your morning jog, you can make it so all the Rattatas that would usually pop up will now fly under your radar.
The update also improves the connection to the Plus by making sure the device stays connected even after entering the Pokémon encounter state, or while interacting with gyms.
[Source: Pokémon Go]
This should address many people's issues with the Plus, though it doesn't address other, more important issues like not being able to catch new Pokémon. They also need to fix the issue where I still haven't been able to find one of the dang things.