No, it is not the Spring Update
According to several sources, Microsoft has pushed out an update for the Xbox 360 that you will see next time that you log into the service. According to our understanding, the update is a small one that contains only fixes and no actual functionally updates.
Our sources tell us that the update is primarily focused on a fix for players having interruption issues that these players have seen while playing a few titles. It is unknown what titles were having the interruption issues.
While it is possible that you might not be prompted the first time that you log in, it is likely within the next day or so that you will get the update. It really sounds like a pretty harmless fix from what we have been able to uncover, and it is targeted at specific titles and users that are experiencing the problem. Our sources tell us that the Dashboard and Kernel will change from version 2.0.7363 to 2.0.7371 once the update has been completed.