Does anyone know if there are plans to update older 3rd party content (specifically subclasses) to fit within the 2024 ruleset? For example, I'd like to play an Echo Knight that gets Weapon Masteries, or a Carrion Raven Barbarian with the new Rage rules.

OR, has anyone homebrewed any of the old 3rd party content to be compatible with 2024 rules?

They’ve not made any announcements about it.

But in the cases you mentioned, both weapon mastery and rage are features of the base class, so it shouldn’t matter if the subclass is updated. You can use the new base class with the old subclass just fine. 

Quote from Xalthu >>

They’ve not made any announcements about it.

But in the cases you mentioned, both weapon mastery and rage are features of the base class, so it shouldn’t matter if the subclass is updated. You can use the new base class with the old subclass just fine. 

While you can use the old subclasses with the new classes according to the rules, D&D Beyond currently lacks support for this for 3rd party subclasses, so it's necessary to use another tool or do it by hand.

And as far as updates to the subclasses like what's in the new PHB, that's up to the 3PP's since they write the material.

Quote from wagnarokkr >>

Quote from Xalthu >>

They’ve not made any announcements about it.

But in the cases you mentioned, both weapon mastery and rage are features of the base class, so it shouldn’t matter if the subclass is updated. You can use the new base class with the old subclass just fine. 

While you can use the old subclasses with the new classes according to the rules, D&D Beyond currently lacks support for this for 3rd party subclasses, so it's necessary to use another tool or do it by hand.

 Oh, thanks. I hadn’t realized.