After starting this thread, I sent an email to Acer. I told them that my A100 has Android 3.2 and the Android Market app, and I asked if it will be necessary to update to 3.2.1 before the 4.0 upgrade next week.
In part, here is their reply:
I have verified your product serial number and found that the unit is covered under the standard limited warranty.
I suggest you to wait for few days as the new version of the operating system would be installed on your system sooner or later.
If you are not getting the new operating system, then you can for sure contact us back again.
Very vague. Well, a few hours after receiving their reply, my Android Market app was updated to Google Play, and I received notification of several app updates. My A100 has not been updated to 3.2.1, however. When I check on the device it still says "Your device is up to date."
The tech support person did not answer my question as to whether it's essential to have 3.2.1 before the tablet can update to 4.0. Does anyone here know? Also, how long ago did you receive the 3.2.1 update? Was it months ago or more recently?