To update your current dox42 Add-In to the most recent version, you need to first uninstall it and then install the most recent version.
Steps
Close Microsoft Word, Excel and PowerPoint.
Select Start > Settings > Apps.
Select the desired dox42 Add-In from the Apps & Features list.
Select the Uninstall button.
Confirm the upcoming message with the OK button.
Follow the installation steps for dox42 Add-Ins.
Result
You have updated your current dox42 Add-In.