Error: Could not load file or assembly or Error while creating instance

Issue:

After upgrading to AVEVA Work Tasks, you might get the following error:

Could not load file or assembly

or

Error while creating instance

Resolution:

If custom assemblies are used for any custom activities, SOA assembles, custom event handler, custom resource provider, or any custom components, you must upgrade the custom assemblies to .NET framework supported version to work with the latest version of product.

Rebuild the custom assemblies with the latest version of product and with .NET framework supported version. Ensure to update the assembly in the appropriate path. If custom assemblies are in GAC, you must update the assembly in the GAC too as GAC for different versions of framework are different.