If you are playing on desktops and want to play in 2D it will now work inside the browser as it did before. It was our intention to have things work like this from the offset but as you all know we had a big squeeze to meet our launch deadline and this was one of the things that got delayed in the process.
Both the livery editor and the race viewer on web now run in WebGL as they did previously when you are set to '2D' mode. Only if you are set to '3D' mode will the desktop application be a requirement.
Note: To receive this update properly on desktops you may need to clear your browser cache, as some files relating to it are cached quite aggressively by web browsers. The easiest way to do this is to press CTRL+F5 while on igpmanager.com/app.