Ace or Ace2 - noob needs to know
 

I'm new to Ace. Am just downloading and setting up today. Some mods i want are Ace2, some apparently are older.

Is Ace2 backwards compatible for older mods?
I guess only one or the other should be installed, or can ace and ace2 coexist?

a thousand thanks for any advice

Ace, Ace2, and Ace3 are all independent and generally not backwards compatible. They can however co-exist quite happily. I run Ace2 and Ace3 between all of my addons at the moment. A nice things about libs is that only the freshest copy will be loaded, just in case several addons all try spawning copies of the same lib.

If you're talking about the libraries themselves, you don't need them at all. Just download and install the addons you want to use - they will come with what they need to function, unless it explicitly tells you to download something else. Doesn't matter if they're Ace, Ace2, Ace3, Rock, Dongle, Cosmos, no framework, etc.

iirc Ace 1 is none embeddable.

You're right. In that case, it still either comes with the addon in its zip file or it explicitly tells you that you need it. :)