Difference between as 1/2/3?

1

Hi
I have been away from actionscript for some time and I am now returning as I need to teach Flash game creation to some students. I have a range of books on the subject but they go back to Flash MX and I have just ordered Fash Games University (also by by Gary Rosenv’ig). My questions are as follows:

  1. Does Flash CS3 or CS4 understand actionscript 1 ? ie backward compatability

  2. Is there a table or brief article that covers the differences between actionscript 1/2/3 ?

  3. Is there an actionscript 4 coming anytime soon ?

Any help would be very appreciated.

Thanks

Geoff