XES is the successor of MXML. Based on many practical experiences with MXML, the XES format has been made less restrictive and truly extendible. In September 2010, the format was adopted by the IEEE Task Force on Process Mining. In September 2016, it was accepted as a standard by the IEEE SA Standards Board.
The format is supported by tools such as ProM (as of version 6), Nitro, XESame, and OpenXES. See www.xes-standard.org for detailed information about the standard.