Jeff Sutherland and Ken Schwaber published the 2011 update of the Scrum Guide.
Here is the list of changes, as it was published bei them in „Scrum Update 2011“ (pdf):
The team of people performing the work of creating an Increment is the Development Team. Regardless of the work performed by individual team members, they are known as Developers.
Development Teams do not commit to completing the work planned during a Sprint Planning Meeting. The Development Team creates a forecast of work it believes will be done, but that forecast will change as more becomes known throughout the Sprint.
Scrum does not mandate a burndown chart to monitor progress. Scrum requires only that:
• Remaining work for a Sprint is summed and known on a daily basis.
• Trending toward completing the work of the Sprint is maintained throughout the Sprint.
Release Planning is a valuable thing to do when using Scrum, but isn’t required by Scrum itself.
The Sprint Backlog is the Product Backlog items selected for the Sprint, plus a plan for delivering them. There is no longer a required concept of “Sprint Backlog items” although that technique can make a great plan. A self organizing Development Team always has a plan.
The Product Backlog is “ordered,” instead of “prioritized,” providing flexibility to the Product Owner to optimize value in his or her unique circumstances.