Negative temperatures and dynamic icons

Good afternoon!
Please help. How can you make dynamic icons for negative temperatures?

For positive values, the icon naming rule works fine: icon.png, icon-0.png, icon-50.png
But it doesn’t work if you specify: icon.png, icon–10, icon–20

Can you please share some more details. Which openhab version are you using? For which ui you want to use the icon configuration (mainUI, BasicUI, HABPanel). Also please share your item and ui configuration of the specific point.

OpenHAB 3.0.0.M4

Number:Temperature localCurrentApparentTemperature2 “Ощущается как [%.1f °C]” { channel=“openweathermap:weather-and-forecast:31d284a61d:local:current#apparent-temperature” }

Text item=localCurrentApparentTemperature2 icon=“test”

test.png, test–10.png, test–20.png