Pokémon GO's latest update is bringing with it some amazing new features, such as Raid Battles and revised gyms, but it also has a rather nasty surprise waiting in store for any players who have resorted to using third-party apps to track monsters.
Any monsters obtained via this method are struck-through with a red line and "may not behave as expected", according to Niantic:
With the announcement of Raid Battles and the new battle features, we are staying true on our commitment to ensuring that Pokémon Go continues to be a fun and fair experience for all Trainers. Starting today, Pokémon caught using third-party services that circumvent normal gameplay will appear marked with a slash in the inventory and may not behave as expected.
We are humbled by the excitement for all the new features we announced yesterday. This is one small part of our continued commitment to maintaining the integrity of our community and delivering an amazing Pokémon Go experience.
The Pokémon GO community is rather divided on the topic of third-party "trackers" which make it easier to locate certain monsters. While some accept this is cheating, others argue that when playing in a sparely-populated region such apps are needed to maintain interest.
Many people also take issue with the fact that Pokémon GO's in-game "steps" tracking system was altered to make it less accurate, and resorting to third-party solutions was the only way of fixing this issue. Niantic quite rightly points out that third-party apps create an additional load on the game's servers, which has the potential to impact the performance of the game for all players.