Upgrading Drupal

Upgrading from 8.1.08 to 8.1.10 Requirements problem

Configuration directory: sync

The directory sites/default/files/config_BMuy5vDgNr_gqApS5j_-RAKT8RTjqDeeHKKiQDrHoarxUO7qrbe7r-GwJxKaPv0W61qzC0-bvQ/sync does not exist.

Database updates
Out of date
Some modules have database schema updates to install. You should run the database update script immediately.

Can you help me

Hello!

My developer informed me today that Drupal 6 will no longer be supported. Our website is on Drupal 6. Can somebody here please tell me if it is mandatory to upgrade to a newer version? I would rather not... but I need to determine if it is a must.

I know we have several modules on our website. What kind of problems can we face if we dont do the update?

Thanks for your help.

I have updated to drupal 7.5. It's the first update to drupal core on this site in a year or so (it was probably on 7.28 before). The update completed ok, but what was odd is that when I visited update.php, it listed a raft of 'missing' modules like this:

User warning: The following module is missing from the file system: content. In order to fix this, put the module back in its original location. For more information, see the documentation page. in _drupal_trigger_error_with_delayed_logging() (line 1128 of H:\root\home\siteloc001\www\mysited7\includes\bootstrap.inc).

Studying migration in D8. I already have custom module of a custom migration working. I can successfully migrate an existing D6 site into D8.

My goal now is to fine tune the migration for a specific content-type. I want to migrate its nodes into (1) of (2) different content-types based on its existing URL-alias. Existing nodes within a certain URL-alias range would become one content type, while others outside this range would be migrated into a second content-type.

For Drupal 7 we were able to extract and have the code in a place like /var/www/drupal7/..... and then use "ln -s" to reference from the website document root most of the files and have own /sites/default... Thus updates in one place and multisites could not see files from another site because not in document root. Found someone had documented it here:
https://www.drupal.org/docs/7/multisite-drupal/secure-multi-site-setup-u...

After updating to 8.1.9 I received a 500 error that stated it couldn't access the web.config file (I'm using IIS 8). I fixed the permissions, then received a 401.3 error telling me the user does not have permissions. I checked and all permissions are fine. I did notice that there were no permissions of the "index.php" file. When adding my AppPool permission, I then get an error telling me either the site is down for maintenance or there is a programming error with the site.

I used "drush pm-update" to run the update. Not sure what my issue seems to be. Any ideas?