There is no maximum delta between versions when completing an IPUP. Hyland suggests using extra care and thorough testing when completing an IPUP for OnBase versions older than 7.2. An IPUP is best completed in OnBase 6.4 and higher.
If upgrading from a version prior to 7.2, note that the Web Server and Application Server architecture has been split.
If upgrading from a version prior to 8.2, note the current dependencies on .NET Core Architecture.
It is strongly recommended to test the Incremental Parallel Upgrade Process in a test environment in order to identify and resolve potential issues.
It is recommended to complete an Incremental Parallel Upgrade within 3-4 months.
It is recommended to complete a business cycle (typically a one month period) before considering the upgrade phase complete and declaring the upgrade a success.