The AssetTrack Transfer Configuration tool is great for moving form updates from one environment to the next, however due to the enhancements made in AssetTrack for ServiceNow 3.0, this feature is not backwards compatible with any 2.x version.
So what does this mean? At a high level, you will not be able to transfer the configuration from a 2.x to 3.0 instance. Once an instance has been upgraded to 3.0+, older config files cannot be loaded.
The following scenario is the usual upgrade path seen by many of our customers and the steps should provide clear instruction on how to manage the forms for upgrading to 3.0.
Transfer your config from PROD to DEV (or Clone)
Production should always be the last instance upgraded. It should also have the latest and greatest forms being used out in the field. If you are currently testing form enhancements on other instances, push those changes live to production FIRST before upgrading to 3.0 or you will have to wait until Production is on 3.0. If you are not cloning down PROD to DEV for this upgrade, transfer the config from PROD to DEV before upgrading to 3.0
Upgrade the DEV instance to 3.0
The first instance usually upgraded is DEV. Upgrade it to 3.0 and continue with your testing.
Upgrade another instance to 3.0 and transfer a configuration
The next instance upgraded is TEST. Once TEST is on 3.0, you can now transfer the configuration from DEV to TEST using the AssetTrack Transfer Configuration tool.
One PROD is upgraded to 3.0, you will now be able to transfer the config up and back down to any instance running 3.0+.