Migrating from version 20.12.xxxx to current version
TAP Studio is built to provide extended compatibility for most automation solutions created with older versions of TAP Studio.
Exceptions: the above is valid for any project created with TAP Studio 20.12.xxxx or older. However, if your automation solution uses the excelDocument automation object (fully qualified name: MissionCritical.Automation.Excel.excelDocument, RPA, Version=220.127.116.11, Culture=neutral, PublicKeyToken=null), you will need to manually update all variables of this type to excelDocument type using the "Choose Type" option within the variables pane from TAP Studio.
After selecting the desired variable, change it's type to excelDocument:
This is required to update all excelDocument variable types to a new version of the target object. After the operation has been finished for all required variables, please save the solution. Now you're all set!