Well, it would be nice if we could use all versions below our current.
I own A6 Pro and could use A4 Pro - A6 Pro to reflect the client needs.

Long time ago I starded with A4 from Sybex but the restrictions with this old release were the main showstopper for me to even start using it for more than a month.

But the executables were sooooo small... 480 k for the exe alone