Yosemite question

Hi, maybe a dumb question, but are the new Applescript features like ASOC/Script Libraries/Using etc mandatory in Yosemite or optional? What I mean is, will I have to rewrite all my existing scripts using the new paradigm/capabilities? Thanks.

There are changes in every Mac OS X version and they are all summed up here including Yosemite.

Thanks, very helpful. I do believe the answer is “optional” – hurray!

And here.