Color White stop working

[Xementhal]

The fixture worked perfectly QLC+ 4. But in one of the latest updates, it had a bug.
It's an RGBW head, and the white color stopped working. I tried to resolve it by trying different fixture configurations, but it didn't work.
It doesn't work in 2D, but it doesn't work in real life either.

[GGGss]

It does not work in 2D. You need to set some dimensions in your fixture definition. (Otherwise, it will show as a 0x0 px in 2D.)
And per community rules, custom fixtures need to be constructed in English.
I doubt that your set pan and tilt maximum are wrong. (A sister fixture with the same name, BeTopper LM70, is also in use.)

If you use the fixture validator: https://www.qlcplus.org/fixture_validator.php you might have already given hints on what is wrong with it.

[Xementhal]

Thanks for your help. The problem isn't with the fixture definition. I'm attaching a screenshot of the four LM70s I have, each with Master = 255, and Red, Blue, and White = 255. As you can see, the white color isn't displayed. The white color doesn't actually turn on on the LM70s either. I've been using those LM70s for a long time, five years or more, with the same fixture, and they've always worked. This seems to have started with one of the last two or three updates.