Engine release notes?

Hi,

I have already posted this message to another group but they suggested I post it to this group which is probably more correct.
I wanted to know if possible where I can view the change logs or release notes of the various versions of the Defender engine and other major components as well.
I searched the net but it seems to me that there is no explanatory page, it is only present for definitions.

Thanks to all and best regards.

Fabio.