Shadow effects look like beta version's shadows but in newest version 1.13

I watched a video on Youtube about someone playing beta versions of minecraft and that made me want to do it so I did. I pulled up Minecraft, went to Launch Settings and added beta 1.1 or something like that to Minecraft. Then I loaded up minecraft beta 1.1 and after realizing that this computer couldn't support it very well, got off and loaded up version 1.13. But when I loaded up one of my worlds, the shadows were the same as the ones from the first versions of minecraft. This is pretty frustrating because it looks bad because it isn't smooth like normal, and makes everything very dark, especially caves which are pitch black.