BGR reported that BlackBerry Enterprise Server 10 would only work with devices powered by the upcoming BlackBerry 10 OS.
The reason why RIM responded so quickly to the erroneous report is that the company is fighting for its life and any nervousness among CIOs and IT departments could lead to a loss of some enterprise business, something that the Canadian based manufacturer can't afford in its current position. With RIM losing market share in most countries, it is counting on the early 2013 release of the new QNX-based BlackBerry 10 OS and the new phones that will run it, to turn things around.
UPDATE: BGR is still sticking to its story and says that companies will still need to run BES 5 along with BES 10 for the latter to work with BlackBerry legacy models. BGR says that RIM has confirmed to them that "BES 10 will need to be installed in either a Virtual Machine or a new server in addition to the existing BES 5 deployment."