well with Version 55 is going to start the RE-Firefox that will end on reaching the 57 stable version
nothing will be like before especially the GUI app customization with so many addons will be put out of the games,
until now in case of any troubles they already always asked for a manual "refresh", now they decided for the hard way (actually the main trouble is not on our side but are the users losted in favour of Google Chrome)
anyway I'm now trying the version 57 Nightly and I'm very good impressed
but I really will miss my dock customizations ....