macOS Sierra 10.12 : Homebrew can't brew upgrade Warning: We do not provide support for this pre-release version
<p>Yesterday I upgrade macOS Sierra, When I brew upgade,appeared error:</p>

<pre><code>     Warning: You are using OS X 10.12.
     We do not provide support for this pre-release version.
     You may encounter build failures or other breakages.
     Please create pull-requests instead of filing issues.
</code></pre>

<p>I search long time for solve for this problem ,</p>

<p>eg:</p>

<pre><code>sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
</code></pre>

<p>or:</p>

<pre><code> sudo chown $(whoami):admin /usr/local &amp;&amp; sudo chown -R $(whoami):admin /usr/local
</code></pre>

<p>And then reboot OS,there are still this problem.</p>

<blockquote>
  <p>/usr/local exists already, it can be writed.</p>
</blockquote>

<p>So,I don't  use brew upgrade, please help,I have a long time can't use it.</p>