If you read my previous post I mentioned that Drupal v7.50 has it's apparent difficulties. I spoke of the issue of the consequences of physically uninstalling modules without removing them from the database. Now I will talk some about the other error that surfaces with the upgrade to Drupal 7.50.

That error is:

4 byte UTF-8 for MySQL is not activated, but it is supported on your system. It is recommended that you [warning] enable this to allow 4-byte UTF-8 input such as emojis, Asian symbols and mathematical symbols to be stored correctly. See the documentation on adding 4 byte UTF-8 support for more information. (Currently using Database 4 byte UTF-8 support Not enabled)

In investigating the issue I found the procedure to enable UTF-8. This involves making changes to the my.cnf file for your MySQL server and to the settings.php file in your Drupal instance. From what I was reading there really isn't much to be gained by it unless your site needs to support things like emojis, Asian symbols, mathematical symbols or other items that need UTF-8 support. None of my sites need this so in hind site (I did go through the procedure ti add this support to one of my sites) I have decided that this truly is not anything I need to be concerned with.

The remaining issue is that with Drush and on the Status Report page there is a note that UTF-8 support is not activated. It was noted that it is a Drush issue (and was fixed in Drush 8.3 but there was no mention of Drush 7 or 9). So for now I'd say unless you need it don't bother enabling it because it can be time consuming depending on the size of your database (because you have to convert all your data BEFORE enabling this).

To enable UTF-8 support:
            https://www.drupal.org/node/2754539

About UTF-8 support for Drupal
            https://www.drupal.org/node/2761183