This is composed of a warning, a vent, and a plea
The warning: backup your custom profiles to an external folder BEFORE initiating an update of your Cura software! - It doesn't behave like typical software, where it'll just update the core software and leave your profiles and preferences intact by default!
The vent: Ultimaker treats the configuration of Cura (config) and the configuration of your 3d printer (profile) as THE SAME THING! That means, when you update your software and it says "do you wish to uninstall the old version? >> [yes] >> do you wish to delete configuration files? >> [yes]," it deletes the profiles, too.
Yes... THOSE profiles. The ones that you've spent countless hours fine-tuning and tweaking to make your 3D Printer work perfectly with that filament you've been using.
DagNabbit, Ultimaker, WHY? Why do you treat these separate software functions (one perfunctory, the other critical) as if they are both equally critical?!
The plea: Ultimaker please, PLEASE, Please split the confirmation dialog into two separate prompts: one for Cura configuration (such as interface preferences, theme, options visible, etc.) and the other for Profile/Slicer configuration (the settings you use for printing), and maybe with a confirmation... For example, the prompting could be like this:
"Do you wish to uninstall the old version? >> Do you wish to delete the software configuration files? >> Do you wish to delete the user Profiles / custom slicer settings? >> ARE YOU SURE? - this will delete print settings such as filament, line height, temperatures, etc."
This at least gives us tech-savvy users, who typically burn through software prompts at light speed, a moment for pause by making the REALLY important prompts stand out!