This is not the first time VMware has announced the vSphere Client is dead (also known as the C# Client), but this time it looks like they have a real alternative i the HTML5 client, that you can try from the Fling site.
I am using the HTML5 client in a Demo/lab environment at work at is working great, VMware is releasing a new version every week.
The next release of vSphere will properly have both the new HTML5 and the Adobe Flash (Flex) Web Client. But lets hope that the latter also will disappear quickly.
Here is a link to the announcement:http://blogs.vmware.com/vsphere/2016/05/goodbye-vsphere-client-for-windows-c-hello-html5.html