If you plan to play online ranked battles (Battle Stadium), use the “Auto Legality” mod plugin to ensure every edited Pokémon passes the stricter 2022-2023 season validation.
This particular build is often recommended on Reddit and GBAtemp for its "goldilocks" balance—new enough to handle modern games, but before some experimental features that caused crashes in early 2023. Here are its standout capabilities: pkhex 22.12.18
Where to find the for older versions?
As a core-series save editor, version 22.12.18 allowed players to perform several advanced tasks: Legality Checking: If you plan to play online ranked battles