Why is networkbehaviour underlined in green?

i don’t understand why networking doesn’t work for me. Is it because i am using the free version of unity?
on the networking scripts it says things like: “the high level API classes are deprecated and will be removed in the future”

130794-screenshot-8.png

Because

the high level API classes are
deprecated and will be removed in the
future

How should we say it more clear? If you had an eye on the development of Unity you may have noticed that they worked on a new networking solution (again). For more details see the UNet deprecation FAQ and the blog about the new network system