I recently updated my MacBook from the latest Yosemite version to the El Capitan public beta. In many screenshots I saw, San Francisco was the default font for the body text of mails and notes. While menus, sidebars, etc. are correctly set in San Francisco for me, the body text of my mails and notes is still set in Helvetica (Neue). Any idea what might be the problem? Thanks! P.S.: As San Francisco does not appear in my font book – that seems to be normal – I also can't change it in the application itself.