Check this nice reddit topic for this subject.
kogsworth's answer is really good and i agree with him.
Of course it's worth it. The syntax might have changed substantially
between 1.3 and 2.0, but the fundamentals of the framework remain the
same. You'll have to learn to deal with dependency injection, two-way
binding, directives, services, filters, etc. What you're learning
today in tech will always become deprecated in the future, but the
time you spent now will help you learn/understand the next big thing.
And the main philosophy behind angular such as declarative style and testable code will not change. It is better to start learning now if you are coming from imperative front-end background.