Fixed a bug where Pokémon would occasionally fail to learn new moves after evolving through a Wonder Trade.
The official for Pokémon X (and Pokémon Y ) was released on April 22, 2015. While officially described as containing "various bugs fixes" to improve the gaming experience, further details from Nintendo Support and the Pokémon Global Link specify several key changes: Patch Highlights Pokemon X: Update 1.5 [Decrypted] 3DS (EUR/USA)...
Resolved an issue where certain captions for Trainer PR Videos in Lumiose City remained locked. Fixed a bug where Pokémon would occasionally fail
: Enhanced data-check functions to detect and prevent unauthorized data manipulation in competitive play. If a player encounters someone attempting to manipulate data, they are now automatically disconnected without the match counting toward their rating. : Enhanced data-check functions to detect and prevent
: The term "Decrypted" in your query typically refers to a modified game file (ROM) intended for use with emulators like Citra, which cannot run standard encrypted 3DS files.
: The update data is stored on the 3DS SD card rather than the game cartridge itself. How to Update Pokémon X and Pokémon Y | Nintendo Support