Network missing in components

Network missing in components. Unity version is 2019.1.2f1
[138216-снимок-экрана-9.png|138216]

Unity Changelog :

Multiplayer: Moved the multiplayer high level API from an extension DLL to a package. Projects should automatically update with a reference to the package the first time they open in 2019.1.

Did you take a look at the package manager?