The update alert had a "download" option which I clicked - no warning or info... Later, after probably (?) applying the current update, I remembered the saved download file and executed it, as I thought I was supposed too (why else suggest I download it?) It seems to have guided me thru an initial installation, with no warning that I might be wiping out my finely working 10-year working version of Mozilla. I could have stopped along the way (maybe?) as it wanted me to "Complete Installation" but I drove on, fearing since I'd already installed it, it was to late to back out. Felt trapped and in fact now have a very different looking (uglier) Mozilla than I was familiar with, and have lost all of my old Bookmarks! There was no warning to save the old once first to later re-install. Basically the install from the downloaded file should have noticed that I already had Mozilla installed and warned me about proceeding, but it did not! Grrrrr! That's my complaint!

Oh, doing this on an HP laptop, Windows 10 with purchased extension of Windows 10 support...