Heartbleed is a security vulnerability found on many web servers. It is due to a bad coding in a program called OpenSSL. OpenSSL is used by many websites to provide a secure connection between the website and the web browser.
We have tested all our servers and they are free of the Heartbleed vulnerability. These checks involved logging into each server and checking for the vulnerable code.
If you are concerned that Heartbleed may effect your website, you can test your site at http://filippo.io/Heartbleed/