99.9% of Roll20 users already have WebGL enabled on their systems, and you can test whether it works for you simply by clicking this link. If your system does not support WebGL, you will not be able to access the Updated Dynamic Lighting or its features.
WebGL leverages the power of your computer's graphics processor to make rendering much faster and smoother. Because it's the same system that Legacy Dynamic Lighting used, if you were able to use that feature before, you will be able to use it now.
We feel that it’s important to note that while many web browsers support WebGL, Chrome and Firefox are the only browsers supported with this release. In addition, Updated Dynamic Lighting has not been tested on Table on Tablet.