If you are using Firefox, a security vulnerability was identified yesterday, and the fix just came out an hour or so ago.
Press the menu button (3 horizontal bars) in top right, press "?" at the bottom of the menu that pops up, press "About Firefox". This will tell you what version you have and will automatically download the latest version - currently 50.0.2 - which fixes the vulnerability. Let it finish downloading, then exit and restart.
If you are using Thunderbird, either select "Help" from the top menu or press the menu button at top right and then select "Help", then press "About Thunderbird", that will tell you what version you have and download the latest version with the vulnerability fixed, then exit and restart.
The vulnerability is present in all platforms, not just Windows.
Press the menu button (3 horizontal bars) in top right, press "?" at the bottom of the menu that pops up, press "About Firefox". This will tell you what version you have and will automatically download the latest version - currently 50.0.2 - which fixes the vulnerability. Let it finish downloading, then exit and restart.
If you are using Thunderbird, either select "Help" from the top menu or press the menu button at top right and then select "Help", then press "About Thunderbird", that will tell you what version you have and download the latest version with the vulnerability fixed, then exit and restart.
The vulnerability is present in all platforms, not just Windows.