Save a backup copy of the message containing the new license key.
Start Oxygen XML Editor plugin.
Copy to the clipboard the license text as explained in the message.
If this is a new install of Oxygen XML Editor plugin, the registration dialog is displayed automatically at start-up. In the
case you already used Oxygen XML Editor plugin and obtained a new license,
go to Window > Preferences > oXygen, Register button.
Select Use a license key as licensing method.
Paste the license text in the registration dialog.