Importing from previous alldata.gdb

Basecamp won't allow me to import alldata.gdb that was created in a previous version.

Here is the story.
I screwed up my current alldata.gdb. This is where all my lists, list folders, waypoints, routes and tracks are stored. I had a lot of stuff in there and I mistakenly deleted more than I intended to delete.
My fault, I screwed that up. My current Basecamp "My Collection" is missing a lot of good stuff.

But I do system and file backups regularly. NOT backup from within Basecamp.

I found the alldata.gdb from February which i want to access. It is in a separate folder on my desktop.
This file was created under Basecamp 4.5.

In the meantime, I upgraded Basecamp to 4.6. I didn't consider this would be a problem.

I select "import" under the file menu and select the February version of alldata.gdb.
I get an error "Unsupported version"

I need to copy, or merge (not replace) data from the February alldata.gdb into my current Basecamp "My Collection"
How do I do that?

Do I need to...can I....revert from Basecamp 4.6 to 4.5? Will this solve the problem?

Thanks!!