In most cases, the need for customers to get this file urgently isn't too big an issue yet because most of the PCs in an Essentials environment will be domain joined, and thus won't receive an automatic update. You can grab the download here.
Here are the details from the download page.
Windows Server Essentials Connector for Windows Server 2012 R2
Windows Server Essentials Connector is software that helps you connect your PC or Mac client to Windows Server 2012 R2 with the Windows Server Essentials Experience server role enabled. It also enables and manages key client-side functionality of Windows Server Essentials Experience. On a PC, it provides client backup, a tray icon and the Launchpad, the Dashboard for management of remote servers, and a VPN profile with the capability of auto-dialing and monitoring client health from the server side. On a Mac, it provides health monitoring and the Launchpad.
You can download the updated connectors here
Before you proceed with this, take a look at the post from the Essentials team where they provide more details, and make sure you check out the comments and updated information.