Firefox 25 unless plans change is set to remove the addon bar, stop the tab bar position been customisable, major design changes to copy chrome's layout and more restrictions. The idea been a more newbie user friendly gui which is familiar to users of chrome and less customisation to keep support requests down (conspiracy theory google pay firefox's bills so these changes requested by google).
Some infos here. Top link has a screenshot to show how bad it is.
Options are for those who wish to avoid changing browsers.
Use the ESR release, v24 will be an ESR release, so it will get security updates for around a year and have the existing gui, as ESR is a feature freeze. One could hope by then firefox dev's change their mind or at least partially go back on their decision so by the time ESR expires things may be better, is also possible by then it may be fixable by addons.
Use a fork, the palemoon and cyberfox dev's have both said they will maintain the existing gui with newer firefox, the palemoon dev said he will code an entire new gui to maintain it if he really has to as he expects mozilla to deliberatly strip out old gui code to make maintaining it harder.
Accept the changes.
Keep using v24 without security updates. not as bad as seems as patching the software is just one way to mitigate vulnerabilities, its not the only way and not all vulns are serious.
We are currently on firefox 23 so 25 is 2 releases away and the next ESR is one release away if looking to switch to it.
Edited by Chrysalis (Thu 15-Aug-13 18:20:56)