I have installed it using the ppa. On LL 3.2 it didn't have any issues, but I've just installed LL 4, and I can't seem to make it work. The program acts like it's working, but when I try to preview different settings or even have it running in the evening, the screen does not change at all. I've tried other programs, but I prefer f.lux, so I'd like to get it working properly. I'm just not sure what the issue is - anyone have any suggestions?