Nintendo’s official 1.5 update for Pokémon Y fixed the infamous Lumiose City bug and added a handful of stability patches. However, the encrypted version (the one you download from the eShop) is locked to your specific 3DS console.
Enhances internet communication protocols for more stable online interactions. Decrypted vs. Standard Updates pokemon y update 15 decrypted 3ds eur usa better
While it didn't add new Pokémon, it was a critical "quality of life" and security update: Pokéball Fixes: Nintendo’s official 1