RGBW2 DDD turn=toggle

According to this page RGBW2 should support http://192.168.x.xxx/white/n/?turn=toggle, but I get "Bad turn!"

I'm trying to use a wifi connected button to switch a light that won't have a wired switch, but without toggle I'm stumped.

Was this feature removed? Can it be added back?

Firmware: 20191216-090536/v1.5.7@c30657ba

No difference with or without the trailing slash.

However, if I switch it to color mode it works. Looks like turn=toggle is missing from the white endpoint.

How do I report this bug to the developers to get it fixed in the next firmware release?

66er any ideas?