you want to block the ff updates - yes ?
otherwise you wake up, with new, auto installed version (as bad as win 10) and half the add-ons no longer work as they are incompatible;
usually I install the new version separately, for a check out before commiting, and have a shortcut like this
"C:\Program Files\Waterfox_43\waterfox.exe" -P -no-remote
to assign a new profile.
This is not an issue, and hasn't been for years.
The only reason it happened before was when add-ons were using the old code/api or whatever it was and Mozilla had a new add-on system in the new version of FF - Developers simply had not updated their add-ons to reflect the next gen system.
If some of your extensions stop working after an update, then blame your extension developer for lazy coding, not Mozilla.
As for Windows 10, it is a better OS than all previous versions of Windows.