Firefox 48 is scheduled to be released on 2016-08-02
release notes: https://www.mozilla.org/en-US/firefox/48.0/releasenotes/ fixed security issues: https://www.mozilla.org/en-US/security/known-vulnerabilities/firefox/#firefox48 (to be disclosed at the time of release)
...and version 48 has a couple of things in store for us:
- multiprocess firefox ('e10s') is starting to be rolled out: 1% of qualified users (no extensions, no rtl-locales, accessibility mode not switched on) will be moved to e10s (this is happening with the help of the "Multi-process staged rollout" a system addon) - https://asadotzler.com/2016/06/06/firefox-48-beta-release-and-e10s/
- redesign of the urlbar dropdown: more results are shown & the dropdown fills the whole width of the browser now - bug 1181078
- the download protection part of the safebrowsing feature will now also detect potentially unwanted software downloads (adware, browser hijackers) by default. this can be controlled through the browser.safebrowsing.downloads.remote.block_potentially_unwanted preference - bug 1265359
- blocking of unnecessary flash content: some flash counting 'pixels', fingerprinting stuff etc will be blocked from loading to improve stability and page loading time. this is happening in the background without any user visible pref to control that - https://github.com/mozilla-services/shavar-plugin-blocklist
on top of that some addon related changes:
- it looks like the enforcement of extension signing is finally put into action and the overwrite through the xpinstall.signatures.required pref will no longer be effective (no guarantees though, as this was postponed a couple of times already). affected users could switch to developer edition or nightly or use unbranded firefox builds. information on how to obtain them should be published at https://wiki.mozilla.org/Addons/Extension_Signing#FAQ by the time of the release.
- redesign of the get addons discovery pane - https://blog.mozilla.org/addons/2016/07/18/a-better-add-on-discovery-experience/
- webextensions are here - https://blog.mozilla.org/addons/2016/04/29/webextensions-in-firefox-48/
as always please feel free to add to the thread as other changes become known or in case there are particular trends in reported new problems on the forums :))