I updated my iPhone app to version 40 a few days ago. Ever since, I cannot use Firefox. I try to open it, and it freezes and shows a black screen (despite having several tabs open). I have tried deleting the app and reinstalling. I had to reopen the each of my old tabs individually. It worked for a few hours but has stopped working again. I have a lot of tabs open and I do not want to keep reinstalling it and reopening all of them to be able to use the app.