The version of Finatra documented here is version 2.x. Version 2.x is a complete rewrite over v1.x and as such many things are different.
For high-level information about the changes from v1.x see the blog post here.
For servers, Finatra builds on top of the features of TwitterServer (and Finagle) by allowing you to easily define a Server and controllers (a Service-like abstraction) which define and handle endpoints of the Server. You can also compose Filters either per controller, per route in a controller, or across all controllers.
Finatra is an open source project that welcomes contributions from the greater community. We’re thankful for the many people who have already contributed and if you’re interested, please read the contributing guidelines.