After years with a fully paid EE subscription, is it possible to stick with our current (older) EE code base and discontinue software updates and support? Updating to newer versions of EE breaks our main modules and EE technical support doesn't support the scope of our technical problems.
I would always check with your legal department, but looking at following in the Magento User Agreement, it would seem that you need to stop using the software:
6.3. Within thirty (30) days after termination of the Software license or this Agreement or expiration of the license term as specified in the Magento Order Form, Licensee shall certify in writing to Magento that Licensee has ceased use of any and all Proprietary Materials and that all copies or embodiments thereof in any form, including partial copies within modified versions, have been destroyed.
In my personal experience, I would suggest always upgrading to the latest and greatest version of Magento. If not for the new features, I would do it for the bug updates. Yes I do know what you mean about breaking your modules, however everyone has to deal with that and everyone has to update those modules regularly.
You are paying for a renewable license to use the software, if you stop paying the yearly fee you need to downgrade to CE. Upgrades are based on the cycle of your business, Large Enterprise goes in 7-10yr cycles, Medium Enterprise 3-4yr cycles, Small Enterprise (which is where Magento EE is pitched), 1-2yr cycles.
If you want to know why it is going downhill, some multi-national consultants gave us some information which is the base for the following discussion. http://www.magentocommerce.com/boards/viewt/viewthread/621306/