Starting in August, Niantic Labs began banning players who violated the terms of use of the mobile game. The most notable of the penalties came from players who used third-party tracking apps, allowing them to find Pokémon with unfair ease. This ranged from simple add-on maps to tricking the GPS in the game.

The developers posted an update on their official website Monday, which details the reasoning behind the original decision to penalize players.

“Some players may not have realized that some add-on map apps do more than just show you nearby Pokémon. Each end-user app can be used as a collection tool by the app creator, invisibly collecting and forwarding data without the knowledge of the end user,” stated Niantic’s CEO John Hanke.

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“Because of this we have had to ban some accounts associated with using these add-on map tools, leading to confusion by some users about why they were banned.” Hanke noted this affected a small group of users, with a majority of the bans given to players using GPS-spoofing technology to falsify their location.

For more, read: Pokémon Go is Stalling Out—Probably Because There’s Not Much Game There

As a result of some changes made to our infrastructure, we are now able to unban this set of accounts,” stated Hanke. Moving forward, the trainers who tested add-on map technology will regain access to their accounts, while the players who used GPS-spoofing technology will still be banned. “Accounts which used apps or websites to remotely capture Pokémon, battle or deploy on Gyms, or harvest resources from PokéStops are also not being unbanned.”

This story originally appeared on EW.com.