If you are referring to colors you set with CSS in a prior version to 115, those older CSS settings no longer work.

No, I believe Pashta is referring to Custom colours within a message, as in my attached screenshot.

I use this extensively, and it is now broken.

Thank-you Andrew. I don't know how to get TB to fix this. I use the custom colours a lot too -- and most of the set colours are either too light for text or too dark to see the difference between them.

I see you've posted this question twice. My inference is that the colors are working but not bright enough for you. Thunderbird uses standard HTML to insert the colors. This may be more an issue with your screen display of colors, not Thunderbird.

NO -- that is not the problem, and it is not a problem with my screen. Before the last update, Thunderbird held the custom colours -- now it does not.