README.md in poltergeist-1.16.0 vs README.md in poltergeist-1.17.0

@@ -7,11 +7,11 @@
 provided by [PhantomJS](http://phantomjs.org/).
 
 **If you're viewing this at https://github.com/teampoltergeist/poltergeist,
 you're reading the documentation for the master branch.
 [View documentation for the latest release
-(1.16.0).](https://github.com/teampoltergeist/poltergeist/tree/v1.16.0)**
+(1.17.0).](https://github.com/teampoltergeist/poltergeist/tree/v1.17.0)**
 
 ## Getting help ##
 
 Questions should be posted [on Stack
 Overflow, using the 'poltergeist' tag](http://stackoverflow.com/questions/tagged/poltergeist).
@@ -78,15 +78,20 @@
 (See also the [PhantomJS building
 guide](http://phantomjs.org/build.html).)
 
 ## Compatibility ##
 
-Poltergeist runs on MRI 1.9, JRuby 1.9 and Rubinius 1.9. Poltergeist
+Poltergeist runs on MRI 1.9+, JRuby 1.9+ and Rubinius 1.9+. Poltergeist
 and PhantomJS are currently supported on Mac OS X, Linux, and Windows
 platforms.
 
 Ruby 1.8 is no longer supported. The last release to support Ruby 1.8
 was 1.0.2, so you should use that if you still need Ruby 1.8 support.
+
+PhantomJS does not support ES6 features at the time of writing this
+document. Setting `js_errors` to `true` can help determine if failing
+tests require Polyfills, although a bug in PhantomJS can cause silent
+failures if using ES6 features like `let`, `const`, etc.
 
 ## Running on a CI ##
 
 There are no special steps to take. You don't need Xvfb or any running X
 server at all.