Fixed Random Matchup disconnects and general online stability.
If you own a physical copy of Pokemon Y , the data on the cartridge is encrypted. Physical 3DS systems handle this encryption natively via hardware chips. However, computers, mobile phones, and gaming handhelds do not possess this hardware.
When you see a file labeled "Pokemon Y- Update 1.5 -Decrypted-", it refers to a technical process that makes the game data readable and modifiable outside of a standard Nintendo 3DS console.
To understand why a "decrypted" version of Pokémon Y Update 1.5 is so significant, it helps to understand how Nintendo secured its software. The Barrier of AES Encryption
However, emulators like Citra cannot read encrypted files directly; they require decrypted game files to run them [2†L28-L30]. A "decrypted" update file has been "unscrambled," allowing it to be read by a computer.