The great thing about languages like C# is that you really don’t need to “catch up”. It’s incredibly stable and what you know about C#8 (Really could get away with C# 6 or earlier) is more than enough to get you through the grand majority of personal and enterprise programming needs for the next 5-10 years.

New language versions are adding features, improving existing ones, and improving on the ergonomics. Not necessarily breaking or changing anything before it.

That’s one of the major selling points really, stability and longevity. Without sacrificing performance, features, or innovation.