Updating the Code of a ipbase Licensed Cisco Catalyst 3750X Switch Stack

Here in the office the Access Layer of our switching infrastructure is handled completely with a 7 unit stack of Cisco 3750X switches.  There is no need for these to do any routing other than intervlan so when purchased 3 years ago we just ordered the IP Base licensing level.  Well from what I can tell there is a universal code base and a licensed feature level of each code revision.  The universal naming convention looks like c3750e-universalk9-mz.122-55.SE1 while the ipbase looks like  c3750e-ipbasek9-mz.150-2.SE6.  What I found is that I do not have the ability to download the universal code of later releases due to my licensing level and possibly the lack of SmartNet I keep on these, but I do have access to the ipbase code.  When attempting to update the code on this stack I was presented with the error

After some searching I found reference to others trying to go from IP Base to Advanced IP Services code having to put the /allow-feature-upgrade switch on the archive download-sw code in order to allow the upgrade as well as it seems a downgrade.  Evidently this feature came about with IOS version 12.2(35).  Now the upgrade progressed and I have happy little upgrades switches.

Another note about this upgrade I found in the official release notes is any upgrade from 15.0(2)SE to later will result in a microcode upgrade which when unmitigated will lead to an exceptionally long restart of the switch.  You can mitigate this either by using the /force-ucode-reload parameter when downloading the code to the devices or by using the archive download-sw /upgrade-ucode privileged EXEC mode command afterwards.