This article refers to Sibelius 7.0 and earlier. If you are looking for your System ID and Activation ID, which are for Sibelius 7.1 and later, please see this article: • For individual copies of Sibelius, the serial number is printed on the back of the original Sibelius CD or DVD case. Some versions with DVD cases will have the sticker inside the case behind the User Guide. • For multiseat licenses of Sibelius 7.0 and earlier, the serial number was included on the invoice or dispatch note that will have arrived with the boxed product when you ordered it. If you have Sibelius 3 or later installed, you can find the serial number by running Sibelius: On Windows: go to Help > About Sibelius.