Emulation is legal. Downloading ROMs for games you do not own is copyright infringement in most countries. Always dump your own cartridge using a 3DS and GodMode9.
For modern players, especially those using Pokémon Bank or HOME transfers, Version 1.4 is . Pokemon Omega Ruby Version 1.4 Download
Released on April 22, 2015, the v1.4 update Pokémon Omega Ruby Emulation is legal
For the vast majority of players, the update should be handled through official Nintendo channels to avoid file corruption or security risks. Pokemon Omega Ruby Version 1.4 Download