[baisq]

What MMOs use UDP? Asking sincerely because I have never seen one.

[koolba]

Anything with real time communications like an FPS would use UDP as stale action data is mostly useless. The latest state of is all that matters.

Most such games will either layer their own streaming channel atop UDP for guaranteed ordered delivery of important messages or use a separate TCP socket as well.

[Daegalus]

all of them, its been like that for a long time. im resurrecting an old mmo, and even then it was UDP.

WoW, FFXIV, ESO, GW2, etc

Some might use TCP for login and character select, but its UDP while playing.

[baisq]

WoW is 100% TCP. idk about the rest.

[xnyanta]

You must not be looking very hard, pretty much every game engine uses UDP as the network transport. There are some notable exceptions like Java Minecraft.