I upgraded from the previous version just now and lost a material and a profile with no warning. Technically the profile just has totally different settings, so maybe lost is not the correct word for it, but the material profile is definitely gone.
It's getting to the point that when there is an update, I dread installing it because I have to spend time "fixing" everything that Cura lost or no longer considers valid. I keep a computer running 3.6 just because I have a ton of dialed in settings and custom printers printing beautifully that I don't want messed with.
It lo