How old a reference book can be before it becomes obsolete?

Question

I have many reference books on different programming languages and was wondering how old is too old.

Answer 1

Just depends how much the language has been updated since that edition of the book.

Answer 2

just look at the version of the language you're trying to learn on the book and on the latest update of the official website of the language

Answer 3

>Short answer:
Books are still relevant 2-4 years. So it's okay to buy an older edition.

>Long answer:
There are always changes every single year, regardless of programming language. However books tend to actually be useful for quite some time.

Python for example from version 2 to 3, had the major change of divisions returning a float instead of an integer. This has massive implications for any company or dev team that relied on integer returns, but for the individual, you won't notice until you try it.

Books are still far more in depth than most online tutorials, be physical or online copies. Even if a change is made, you'll find out soon enough after attempting to practice. You'll just think (oh, so that's different).

I wouldn't depend on anything older than 4 years for absolute accuracy, but it depends on the language and the content of the book. Some content in many books written far longer than 5+ years still are relevant.

Answer 4

This q. has no definite answers. Depends how much the language, framework has been updated.

Example: Angular 1 books and references are totally obsolete in Angular 2 (because it re-written from scratch), at the same time, C# 1 books are totally fine for C# 6. Same for Java 1 and Java 8.

Just googling for 2 minutes and reading the change-logs you'll know if your stuff is obsolete or not.