Syntax highlighting for JavaScript does not support template literals on Stack Overflow, but does on Meta

I just realized that syntax highlighting for javascript is different on Meta Stack Overflow compared to Stack Overflow.

Meta:

Stack Overflow:

Ignoring the different colors, you can see that the template literals are being highlighted in the Meta example, but on the Stack Overflow example, they are being treated as normal code.

Why is this? Is there any reason as to why the syntax highlighting is different on one site than another?

Inspired by this question - Add support for template literals to the JavaScript syntax highlighter