Avoid updating via the eShop if you are using specific older ROM-injection methods, as it may break compatibility.
The Pokémon X Version 1.5 update was a critical stability patch released on April 23, 2015. It primarily addressed online connectivity issues and security measures for the official Nintendo 3DS game . Update 1.5 Core Changes
Add your decrypted .3ds file to the emulator library.
Resolved bugs causing disconnects during Random Matchups and Online Competitions.
Use a title manager like FBI to install the update.