Since it doesn't show version number on website I therefore never know if a new version is out or not so I just download every 6 months or so and uninstall my version for whichever is on the website. It's been about 6 months since last time so I downloaded the app from website this morning and I started the uninstall of 3.1 at that moment, and I waited 20 minutes and I got tired and went to bed. Now it's the after-noon and the app is still showing the uninstall window and the yellow line has not advanced.
@Strange-Realms O.K. the new version since 3.0 shows a version number on the bottom of the right click menu for the program by the windows clock. F.lux will check for updates every single day.
Just run the new setup file after closing the uninstall and you should be fine.