@ventilator: That update thing seems to have changed with A7.
Otherwise I have no explanation for the hugh file size of the updates. They are as big as the trial download afaik.

@JustOneOldMan:
Applying the key is pretty easy. You copy and paste the .key file into the main 3dgs folder.
Example:
C:\Programs\GStudio7\

That should be all you have to do

Oh and yes the trial version is the full version but limited to the "trial-limits" depending on the key (licence) specific features get "un-locked".