Upgrading From OnBase 12 or Earlier - Upgrading From OnBase 12 or Earlier - OnBase - Technical Requirements Overview for New Installations and Upgrades - OnBase/Technical-Requirements-Overview-for-New-Installations-and-Upgrades/English/Foundation-22.1/Technical-Requirements-Overview-for-New-Installations-and-Upgrades/Part-8-Technical-Support-and-Upgrade-Information/Upgrading-From-OnBase-12-or-Earlier - English - Foundation 22.1

If you are performing Incremental Parallel Upgrades from OnBase 12 or earlier, it is recommended that you deploy two separate Application Servers: one Application Server running Microsoft .NET Framework 4.0 for OnBase 12 or earlier, and one Application Server running a currently supported version of Microsoft .NET Framework for OnBase Foundation 22.1. This will help you to avoid compatibility issues with different versions of Microsoft .NET Framework while performing the upgrade.