I got this error Failed to load ‘Assets/scenes/impossible mode.unity’ because its serialized file version is higher than what this version of Unity supports. and I updated to the latest version like some of the answers said to do but it still will not work please help, this is the second time it happened and I have not updated unity since last week
@mhyland
Try do this :
In editor
Open Help → Reset packages to defaults.
It worked for me.
Make sure to back up your current project just in case 