I suppose FF x64 may not be affected then ... I also see that uB0 has been updated to 1.14.4 now. I can't follow all the sequence of the chit-chat, but it may still be safer to downgrade to 1.13.8 as I am on FF 55.0.3, and switch off update till FF 57? @Brummelchen I always have backups. Btw, it is a PITA that Mozilla removed the version no. from add-ons some time ago. There is an add-on to bring it back, but I think it will not be ported to WebExtension. Edit: @mood Thanks, I saw your post here, where this discussion should have been, so I guess 1.14.4 should be OK now, and I don't have to do anything. I never experienced any loss of settings.