FromSoftware says Elden Ring's popular Seamless Co-op mod is 'definitely not something we actively oppose,' and may even 'consider ideas like that with our future games'
One of the reason why seamless coop is so good is you can play with mods without having to go offline and disable anti-cheat. I fully expect their implementation of this won't allow for that.
The fact that I can't do something as simple as turning off that god-awful chromatic aberration without anti-cheat banning me for cheating is so ridiculous. It's so bad that I only play offline and at the moment, Seamless Coop is the only way I can play multiplayer.
It's so good for more reasons than just being able to use other mods safely! It's really nice being able to transition between areas without having to resummon, how some progression/unlocks are shared, and that all connected players get to use Torrent and spirit ashes.
The online for seamless coop isn't actual online, it's limited to the functionality of the mod and doesn't use the official servers. You can in principle get cheaters on that, but most people have it setup to only connect to friends. And when you are using mods you are probably just having fun and playing for the memes instead of being a hardcore PvP player.
I personally love seamless coop, I had hoped FromSoft would have made the coop like that from the beginning. So happy mod makers are putting in the time to make it work. I've played over 100 hours with my brother and had so much fun. I can recommend mods like The Convergence as well, combined with seamless it's so much fun.
I'm talking about offline/online generically here, not whether it's using the official servers. I know it's not using the official servers which is why you can play without anti-cheat
Their anti-cheat implementation could definitely use some work. Either that, or just give players the option to disable chromatic aberration, use ultrawide etc.
I played the entire game offline, with the exception of a few specific spots. Sucks.
The ultimate solution is to allow for P2P online with official servers as the default, and just warn people that you might encounter cheaters if you use P2P. Can even go a step further and separate the player pools between unmodded and modded clients. So you can play online with mods, but run the risk of encountering cheaters. P2P should mean you can ban certain people from invading you due to hacks or high ping similar to DSCM back in the day, but in-game.