README tuning for different Selenium[:2] versions

Author: Tatu Aalto

README.rst

@@ -53,6 +53,62 @@ See `Robot Framework User Guide`_ for more information.
 A demo project illustrating how to use this library can be found from:
 https://bitbucket.org/robotframework/webdemo
 
+Differences between SeleniumLibrary versions
+============================================
+
+Selenium versions
+-----------------
+
+There are three main version of Selenium: `Selenium Remote Control`_ (RC or Selenium
+1), `Selenium 2`_ and `Selenium 3`_.
+
+The Selenium RC works only with major browsers that has JavaScript enabled. It
+also requires a selenium server which automatically launches and kills browsers.
+The Selenium RC is not anymore maintained by the Selenium.
+
+The Selenium 2 supports Selenium RC and Selenium WebDirver. Selenium WebDriver
+does not need separate server to launch and kill servers and it has simpler
+and more concise API then Selenium RC.
+
+The Selenium 3 supports only Selenium WebDirver and has started to adopt
+the `W3C WebDriver`_ specification. If excluding the dropped Selenium RC
+support, Selenium 3 is a drop in replacement for Selenium 2.
+
+Selenium support in Robot Framework
+-----------------------------------
+
+The SeleniumLibrary version up to 2.9.2 supports only the Selenium RC.
+
+The Selenium2Library versions up to 1.8.0 and from SeleniumLibrary 3.0.0
+version onwards supports Selenium 2 and 3
+
+Python support
+--------------
+
+The SeleniumLibrary version up to 2.9.2 and the Selenium2Library
+versions up to 1.8.0 supports only Python 2
+
+Starting from SeleniumLibrary 3.0.0 version onwards Python 2 and Python 3.3+ are
+supported.
+
+History
+-------
+
+The SeleniumLibrary up to 2.9.2 version was actively developed by using the
+Selenium RC. When the Selenium 2 reached mature enough state, the Selenium2Library
+was forked from SeleniumLibary and modified to use the Selenium WebDriver. The
+SeleniumLibrary, with Selenium RC support, active development ended
+when Selenium RC was deprecated.
+
+When Selenium 3 was released it was adopted by the Selenium2Library
+because Selenium 3 is a drop in replacement for Selenium 2. Also the
+Selenium2Library relies only on the WebDriver technology and it did not
+need any changes to support Selenium 3.
+
+In release 3.0.0, it was decided to rename the Selenium2Library back to
+SeleniumLibrary. This was done because the name more resembles what the library
+supports and enables.
+
 Support
 -------
 
@@ -78,6 +134,10 @@ information:
 .. _INSTALL.rst: https://github.com/robotframework/SeleniumLibrary/blob/master/INSTALL.rst
 .. _BUILD.rst: https://github.com/robotframework/SeleniumLibrary/blob/master/BUILD.rst
 .. _Robot Framework User Guide: http://robotframework.org/robotframework/latest/RobotFrameworkUserGuide.html
+.. _Selenium Remote Control: http://www.seleniumhq.org/projects/remote-control/
+.. _Selenium 2: http://www.seleniumhq.org/projects/webdriver/
+.. _Selenium 3: http://www.seleniumhq.org/projects/webdriver/
+.. _W3C WebDriver: https://www.w3.org/TR/webdriver/
 .. _robotframework-users: http://groups.google.com/group/robotframework-users
 .. _Robot Framework Slack: https://robotframework-slack-invite.herokuapp.com/
 .. _documentation is also available: http://robotframework.org/SeleniumLibrary/Selenium2Library.html