Same question here
I expect you can but why would you want to. I my experience ADE 1.72 works, for some people later versions fail.
Yes you can upgrade.
1) Deactivate ADE 1.7
2) Install ADE 4.0
3) Activate ADE 4.0.
It seems installing latest ADE (4.0.3) won't uninstall older version (3.0 in my test).
How do you guys solve this in your enterprise deployment?
The current version of ADE doesn't uninstall older version of ADE. The workaround is to uninstall older version and install new version through batch script.
But having a separate enterprise installer is an ideal way, we will consider this request in our future release.
Thanks Dominic for the reply!