I now get a message that the current version will not support the upgrade to V10, and can find no way to insert my activation key.
When you go to “Menu / Help / License” if you previously downloaded eM Client V9 from the eM Client website, you will be able to activate your license or deactivate and reactivate with your license you received by email in the field.
However if you previously installed eM Client V9 via the Windows store then there is no license field to activate the same or any later version as @Gary advised in the thread below.
So if you purchased a V10 upgrade from the eM Client website directly and you want to use that version, then you would have to first make a backup of eM Client via “Menu / Backup” and then once done uninstall the Windows store version and “delete the mail database if asked”, and then download eM Client either via the link in your email or via the eM Client download page & install.
Then skip the setup and then restore your backup via “Menu / File / Restore”. Then once restored, go to “Menu / Help / License” and enter your new V10 license and activate & will be good to go.