+Documentation
+-------------
+
+See the documentation page at [gggeek.github.io/phpxmlrpc](https://gggeek.github.io/phpxmlrpc) for a list of the
+library main features and all project related information.
+
+The user manual can be found in the doc/manual directory, in Asciidoc format: [phpxmlrpc_manual.adoc](doc/manual/phpxmlrpc_manual.adoc)
+
+Release tarballs also contain HTML and PDF versions of the manual, as well as an automatically generated API documentation.
+
+*NB: the user manual has not been updated yet with all the changes made in version 4. Please consider it unreliable!*
+
+*You are encouraged to look instead the code examples found in the demo/ directory*
+
+Upgrading
+---------
+If you are upgrading from version 3 or earlier you have two options:
+
+1. adapt your code to the new API (all changes needed are described in [doc/api_changes_v4.md](doc/api_changes_v4.md))
+
+2. use instead the *compatibility layer* which is provided. Instructions and pitfalls described in [doc/api_changes_v4.md](doc/api_changes_v4.md##enabling-compatibility-with-legacy-code)
+
+In any case, read carefully the docs in [doc/api_changes_v4.md](doc/api_changes_v4.md) and report back any undocumented
+issue using GitHub.