Unable to import policy template from DLP 10.5 to 12.5

We need to add a substantial number of policies from old 10.5 instance to 12.5. When we export policies as XML templates and put them in on the 12.5 Enforce, they do not show up on the Import Temple UI. "Native" 12.5 policies work fine.

Anyone has an idea why it does not work, is it supposed to work between version at all, or any other issues?

Thanks!

Alex