The 21st of May 2014 was a big day in the life of vSphere 4.x as it marked the official beginning of the end. The product and its associated pieces are no longer under general support. this means that security fixes only from now on. Therefore if you have not started your upgrade plan now is the time to do so. You need to be looking at moving up your version.
Other products that are added to this are Lab manager 4.x, vCenter 4.x, vCenter Update manager 4.x,
The document below shows the current status of VMware products: