cPanel & WHM 11.34 reaches End Of Life October 15, 2013. That means there is only one month left in the life cycle.
In accordance with our End of Life Policy [http://docs.cpanel.net/twiki/bin/view/AllDocumentation/InstallationGuide/LongTermSupport], cPanel & WHM software release 11.34 will continue functioning on servers after reaching end of life. No further updates, including security fixes, or installations will be provided for 11.34 after the end of life date.
All customers currently using cPanel & WHM software release 11.34 are advised to begin planning the upgrade to cPanel & WHM software release 11.36 (EOL Date: January 2014). If you desire assistance with your migration plans, please contact our technical support team at https://tickets.cpanel.net/submit/. Our professional staff will help with recommendations, migration assistance and more.
As cPanel verion 11.34 has officially reached it's end of life per cPanel and will no longer be receiving security updates, it's extremely important that you ensure you're on the latest stable version of cPanel (11.38 as of this post).
If your VPS is still running CentOS 4.x, this will require purchasing a new VPS and migrating your data to the new CentOS 6.x system. As CentOS 4.x has been EOL for some time now, this is yet another reason to get upgraded as it no longer receives security updates either.
Please contact support if you have any questions regarding what version of cPanel you're running. If you've not modified the default update settings, and not received any "Unable to update" emails from cPanel, then you're most likely on the latest stable version already.