Profit? Well, I didn't make money from filing a bug about redshift, but I did get the lovely little application running on my computer again.
Since jumping to an testing install of Plasma 5 in my upgraded Kubuntu, I've been filing bugs as I find things not working. It took me a few days to notice that redshift no longer worked, because I didn't always use it. But when I had my eyes dilated for my annual eye exam, I needed it! And it crashed.
I love filing bugs using ubuntu-bug from the commandline. I would love to see KDE build this capability as well, because the little application gathers useful information automatically, and uploads it to the bug tracker. Man ubuntu-bug says it reports problems to your distribution's bug tracking system, using Apport to collect a lot of local information about your system to help the developers to fix the problem and avoid unnecessary question/answer turnarounds. Dr. Konqui does this sometimes, but a little cli app would be nice as well.
You can read my bug report here if you like, but to make a long story short: there is still no working Plasma 5 widget, but redshift is a commandline application. The kindly person who answered my bug report sent me to the website, where I found that I could create my own config file, which might be a workaround to the lack of a widget, but it works. The gtk widget did not work, by the way.
Writing a config file sounds daunting, but I just copy/pasted the working config on the website, changed it to fit my system, and saved it as ~/.config/redshift.conf
In the commandline, when I typed redshift & - my screen pinked up a bit. Lovely!