I have downloaded this update to explore new feature from this version. They added new option under the advanced settings option. This new option you can hide or show web fonts. That will help to reduce the data usage from FireFox browser. So we can call it an important update.
New version willn't use and background data when meta refreshes is used by a website. That will also help you to save your data. Android web run-time is now not supported with firefox web browser. Initially, it's very useful to update. You should download it.
Firefox is now updated to v47.0, APK file size of this version is 37.94MB. This update is supported for Android 4.3+ Devices.
You can download apk file of this update form below link
Firefox APK to Download