title: Upgrading to Laravel 5.2 invalidates all sessions
body: <p>Upgrading from Laravel 5.1.17 to 5.2. My <code>config/auth.php</code> originally contained:</p>
  
  <pre class="lang-php prettyprint-override"><code>'driver' =&gt; 'eloquent',
  'model'  =&gt; 'Project\User',
  'table'  =&gt; 'users',
  </code></pre>
  
  <p>New file is the same as the default, except with the updated namespace.</p>
  
  <pre class="lang-php prettyprint-override"><code>'defaults' =&gt; [
      'guard' =&gt; 'web',
      'passwords' =&gt; 'users',
  ],
  'guards' =&gt; [
      'web' =&gt; [
          'driver' =&gt; 'session',
          'provider' =&gt; 'users',
      ],
      'api' =&gt; [
          'driver' =&gt; 'token',
          'provider' =&gt; 'users',
      ],
  ],
  'providers' =&gt; [
      'users' =&gt; [
          'driver' =&gt; 'eloquent',
          'model' =&gt; Project\User::class,
      ],
  ],
  </code></pre>
  
  <p>My env <code>SESSION_DRIVER</code> is <code>redis</code>. I did not clear anything from Redis. (Note, this also happened in my other projects where driver was <code>file</code>, but I didn't care about it as much for them.)</p>
  
  <p>I have two branches, L5.2 and master (which is on 5.1.17). After switching branches, I simply run <code>composer install</code></p>
  
  <blockquote>
    <p>If I <strong>login</strong> on <strong>master</strong>, then switch to <strong>L5.2</strong>, I am logged out<br>
    If I switch back to <strong>master</strong>, I am logged back in<br>
    If I <strong>login</strong> on <strong>L5.2</strong>, then switch to <strong>master</strong>, I stay logged in<br>
    If I switch back to <strong>L5.2</strong>, I stay logged in</p>
  </blockquote>
  
  <p>I'm hesitant to upgrade if it's going to invalidate all of my users' sessions and force them to login again. Is there a way to avoid this?</p>
  
  <p>The only other files that were modified were <code>composer.json</code>, <code>composer.lock</code>, <code>app/Exceptions/Handler.php</code>, and <code>config/app.php</code>; nothing that touched Auth.</p>