This release focused on improving rendering speed and MathML support.

For more information checkout

• https://github.com/mathjax/MathJax/issues?milestone=2&q=is%3Aclosed
• http://docs.mathjax.org/en/latest/whats-new-2.5.html
• http://www.mathjax.org/mathjax-v2-5-beta-now-available/