It can be safely installed over a Pokémon X base game from any country (USA, EUR, JPN).

: Necessary for any remaining local or wireless features.

So, why should players bother updating to Version 15? Here are some benefits:

The version 1.5 update (often appearing as part of later patch sets, sometimes referred to internally as higher sub-versions in community databases) serves as the final, most stable patch for Pokémon X and Y.

While 3DS consoles and games are normally region-locked (e.g., a US console can't play Japanese cartridges), custom firmware allows for "Region Free" play. A "World" or "Region Free" CIA of the v1.5 update is designed to work across any 3DS console, regardless of its original region. Common Installation Questions Can I still update?