I use VirtualBox with Windows 7 SP1 x64 Ultimate. When I check for the latest update it says there is none.
However, looking at the official website, I don't have the latest stable version: https://www.virtualbox.org/wiki/Downloads
Is VirtualBox's update manager broken, or does it just indicate major updates?
EDIT (2014-11-27): The check for update finally suggested the latest version.
Best Answer
I think the problem is since v4.3.14 VirtualBox enhanced the internal security that caused problems with many anti-virus and other software (only under Windows host), eventually make all guests unable to start (I got the same problem too). So the developer disabled the update notification after that, currently it is not sure when it will be resume.
As mentioned by AlphaCluster, you can download and install the latest version manually. However be aware you might get the same problem.
Here is the latest discussion on this issue, look like it still have similar issue on v4.3.20.