https://www.mozilla.org/en-US/firefox/49.0.2/releasenotes/
https://www.mozilla.org/en-US/firefox/android/49.0.2/releasenotes/
https://www.mozilla.org/en-US/security/known-vulnerabilities/firefox/#firefox49.0.2
https://www.mozilla.org/en-US/security/advisories/mfsa2016-87/