Document upcoming changes in Ranch 2.0

doc/src/guide/book.asciidoc

@@ -3,6 +3,8 @@
 
 = Ranch User Guide
 
+= Interface
+
 include::introduction.asciidoc[Introduction]
 
 include::listeners.asciidoc[Listeners]
@@ -13,8 +15,16 @@ include::protocols.asciidoc[Protocols]
 
 include::embedded.asciidoc[Embedded mode]
 
+= How to
+
 include::parsers.asciidoc[Writing parsers]
 
 include::ssl_auth.asciidoc[SSL client authentication]
 
+= Advanced
+
 include::internals.asciidoc[Internals]
+
+= Additional information
+
+include::upcoming_2.0_changes.asciidoc[Upcoming changes in Ranch 2.0]

doc/src/guide/upcoming_2.0_changes.asciidoc

@@ -0,0 +1,29 @@
+== Upcoming changes in Ranch 2.0
+
+The following changes will be done in Ranch 2.0. In most
+cases an alternative is already available in the most
+recent Ranch version.
+
+* The function `ranch:start_listener/6` has been deprecated
+  in favor of `ranch:start_listener/5`. The number of acceptors
+  was removed and will be taken from the transport options.
+
+* The function `ranch:child_spec/6` has also been deprecated,
+  in favor of `ranch:child_spec/5`.
+
+* The function `ranch:accept_ack/1` has been deprecated in
+  favor of `ranch:handshake/1,2`.
+
+* The socket will no longer be passed to the protocol when
+  starting it. It will be available as a return value from
+  `ranch:handshake/1,2` only.
+
+* Starting from Ranch 2.0 it will no longer be allowed to
+  pass Ranch options along with socket options as a proplist.
+  The only forms allowed will be the `ranch:opts()` map or socket
+  options as-is. The `ranch:opts()` map must be used in case socket
+  options also use a map.
+
+* The `socket` option will be removed. A more viable solution
+  is to define a custom transport module that returns a fresh
+  socket when `Transport:listen/1` is called.