Upgrade Workflow Designer by uninstalling and reinstalling the product on each client machine.
Visio Workflow Designer client support history The SDL Web 8.5 Workflow Designer client has a number of changed third-party software prerequisites compared to SDL Tridion 2013 SP1 HR1 or SDL Web 8 with Cumulative Update 1 applied.
Upgrading Workflow Designer client If you have upgraded your Content Manager databases and Content Manager server, and if you are logged on to the client machine as an administrator user, uninstall your existing client, then install the new one.