In a recent debate with Hasso Plattner, Chairman / Co-founder of SAP, Salesforce.com's Co-founder Marc Benioff made the following remarks:

"All 41,000 Salesforce customers are on the same version. When we release the new version in June, we don't break the links. In some cases they have to re-implement..."

This means that Salesforce.com CRM customers will be required to re-implement, in some cases, when the Summer '08 upgrade rolls out in June.

For more information on the debate, check out the news story.