Upgrading Drupal

Can somebody help me understand the Drupal 6 LTS patch process.

Can I simply do the following and it will bring my up to current security release (including past patches since 6.38)?

1. Download drupal-core-sa-2018-004-d5-2965601-43.patch

2. Move the patch to my drupal directory

3. Execute: patch -p1 < drupal-core-sa-2018-004-d5-2965601-43.patch

After updating from drupal 8.4.5 to  8.5.4 I am getting this error. 

The website encountered an unexpected error. Please try again later.</br></br><em class="placeholder">InvalidArgumentException</em>: Field  is unknown. in <em class="placeholder">Drupal\Core\Entity\ContentEntityBase-&gt;getTranslatedField()</em> (line <em class="placeholder">580</em> of <em class="placeholder">core/lib/Drupal/Core/Entity/ContentEntityBase.php</em>).

What can be the issue?

Thanks

I have upgraded the Drupal core 8.5.3 but I am unable to login with Github when we click github icon it is showing the errors.

Hello.  My company is considering upgrading from Drupal 7 to 8.  The vendor who will be doing it warned us that the domain access module we use is, under 8, in alpha.  Is that something I should be concerned about?  Does it work fine under 8 or would you not recommend using it until it matures a bit more?  

Im been trying to update my database using the web UI. Im running 8.5.3 

I have 8 pending updates as below

Hello Evebody,

For security purpose and to follow Drupal recommendation we make an update from Drupal version 7.56 to version 7.59.

Security advisories : https://www.drupal.org/SA-CORE-2018-004 ( If you are running 7.x, upgrade to Drupal 7.59 )

Problem is that after update performing we make a vulnerability test with Drupalgeddon2 ruby file and it woks well like on Drupal 7.56 version.