How do you confederate as Empire in 5.0+?

[Nico]

We used to have to get Electors to 10 on the Fealty, but since then none of them have offered to Confederate, and there is no option in Diplomacy. I don't understand how things work now; they keep changing every patch.

[LORD-ORION]

With the upgraded Karl Franz's Electoral Machinations mechanic after researching it in the technology tree, you can confederate any Empire faction using Prestige.

[CrUsHeR]

For Elspeth and Gelt - the good old way.

[StrangestEcho]

Factions other than Franz now confederate the generic way; via the confederation tab in diplomacy menu. A faction's willingness to confederate is based on their relative faction strength, relationship with the player faction, how threatened they are by other factions, etc.

[pascal.difolco]

Originally posted by CrUsHeR:

For Elspeth and Gelt - the good old way.

This, and really it's super easy, they will beg for confed as soon as their armies got wrecked, which happens very frequently ^^
So to confed KF ally him and borrow his armies or send them to battle after dangerous enemies