Yes, not only can PolicyPak DLLs be upgraded from one version to another, they can be downgraded from one version to another as well. The warning, however, is that any deleted items within the Pak will also be “dropped” from within the Group Policy data. So, please upgrade and download your paks with caution. See the section “Version Control of PolicyPak Extension DLLs” in the PolicyPakQuickStart guide.