title: C++14 support in GCC is experimental
body: <p>Quoting from the <a href="https://gcc.gnu.org/projects/cxx1y.html" rel="nofollow">GCC page on C++14 support</a></p>
  
  <blockquote>
    <p>Important: Because the final ISO C++14 standard was only recently published, GCC's support is <strong>experimental</strong>. No attempt will be made to maintain backward compatibility with implementations of C++14 features that do not reflect the final standard.</p>
  </blockquote>
  
  <p>I could not find the official GCC definition of <code>experimental</code>. Does it only apply to backward compatibility wrt non-standard features, as the last sentence mentions? Or does it also indicate stability, or lack thereof? An earlier sentence on the same page says</p>
  
  <blockquote>
    <p>C++14 features are available as part of the "mainline" GCC compiler in the trunk of GCC's Subversion repository and in GCC 4.8 and later.</p>
  </blockquote>
  
  <p>To me, this suggests stability. Is this the case? In particular, my question is about GCC 4.9, since that is the earliest version with full C++14 support, according to the aforementioned page.</p>