Hello,
Symantec does renew the License. However, you get a choice to renew to SEP 11.x OR to SEP 12.1.
Secondly, since you are carrying SEP 11.0.6100 (RU6MP1) which is a End of Life by - 2011-07-05 - Check this -
http://www.symantec.com/business/support/index?page=releasedetails&key=54619
We request you to make sure you are carrying the Latest Version of Symantec and It is important to maintain consitency in the SEP 11 - check article below:
About Maintaining Consistency of Software Versions throughout a SEP 11 Organization
http://www.symantec.com/docs/TECH131660
Latest version of SEP 11.x is SEP 11.0.7101, check this -
Migrating to Symantec Endpoint Protection 11.0.7101 (RU7 MP1)
http://www.symantec.com/docs/TECH171552
In reference to annual renewal invoice and the Question about the Annual cost - I would suggest you to speak to Licensing Department, You can contact Symantec Licensing Department for the same.
Website: http://symantec.custhelp.com
Phone number: 1-800-721-3934
Email: license@symantec.com
Renewals
To renew or view details of your Symantec support contracts visit our License Renewal Center.
License Programs and Support
Learn about each of Symantec's Buying Programs and various levels of support.
Activation & Product Upgrades
For product registration, activation or obtain an upgrade for your product, log into our Licensing Portal.
It is always recommended you to Migrate your License to the SEP 12.1 (incase the License is under valid License Period)
How to upgrade your SEP11 license to SEP12 online
https://www-secure.symantec.com/connect/articles/how-upgrade-your-sep11-license-sep12-online
(Note: This is completely FREE)
Once, this is done you could download the Software SEP 12.1 as well as the License and then Migrate the SEP 11.0.1000 to SEP 12.1
Upgrading or migrating to Symantec Endpoint Protection 12.1
Hope that helps!!