Debian released Mozilla Firefox 52, which haves the following features that improves the privacy of the internet users:

1.- Deleted Battery Status API.
2.- Removed the support of NPAPI-based plugins (Flash, Silverlight, Adobe Acrobat, Java).
3.- Added user warning for non-secure HTTP page with logins.

And many other features.

For more information, please follow this links:

https://www.mozilla.org/en-US/firefox/52.0/releasenotes/
https://packages.debian.org/source/unstable/firefox
http://metadata.ftp-master.debian.org/changelogs/main/f/firefox/firefox_52.0-1_changelog

Please update Iceweasel into version 52 (including language packs, of course).

Thanks