We can convert the rules for you from the old .XML to the new .DB format. However, due to the differences between the versions some objects will not be carried over, namely bridges and usage records will not be converted. If you would like us to that, please submit a ticket and attach your XML file.
Alternatively you can recreate your ruleset from scratch as it's now possible to have a more compact ruleset. For example, if you used to have a bunch of identical rules for each IP address, in the latest version you will be able to use so-called tracking/streams. This allows you to have individual limits and quotas under a single rule.