There have been some (fairly minor) changes to the English Standard Version (ESV) at the end of 2011. You can read about this on The Gospel Coalition blog. This article contains a letter from the President of Crossway about these changes. It also provides a link to a complete listing of changes to the ESV. I do see these as fairly minor revisions. Many of the changes make the English read more naturally, which I view as a good thing.
The most potentially significant changes to the ESV concern the reduction of the usage is the word ‘slave’ in the New Testament in passages such as 1 Corinthians 7. But it should be noted that the word ‘slave’ is still used in a number of other passages in the ESV. The Gospel Coalition blog article also includes a video of a discussion by the ESV Translation Committee on the word ‘slave’.