Drupal 8.x

I've been trying to upgrade from 8.6.16 to 8.7.1... After issuing "composer update drupal/core --with-dependencies," everything seemed to get upgraded but I still had to apply the database updates. So after trying both "drush updatedb" and using the update.php approach, I keep running into a wall.

Here's where everything stands right now:

Debian Buster

Apache 2.4

PHP 7.3.4-2

Drupal core 8.7.1

Bootstrap 8.x-3.19

Admin Toolbar 8.x-1.26

Coffee 8.x-1.0-beta2

ISSUE:

I'm attempting to install a subtheme but, after going through the instructions, it's not appearing under "Appearance".  The instructions I'm using can be found here:

https://drupal-bootstrap.org/api/bootstrap/docs!Sub-Theming.md/group/sub_theming/8.x-3.x

Hi Drupal Community,

I was using the Add to Calendar module for adding my events to calendar. However I found that it has issues with timezone, the time I give in my event is date field is not getting saved correctly in my Calendar (Outlook).

Any time added to event is being converted to UTC format and processed.This is bringing an issue to add to calendar feature as the times are not matching.

Same issue mentioned in https://www.drupal.org/project/addtocalendar/issues/2924790

We are running a number of Drupal instances where Drupal core is at version 8.6.14. Noticing there was a core update we went on to the dev site to update to the latest version 8.7.1 through the console using the commands we normally use

drush sset system.maintenance_mode 1
drush cr
composer.phar update drupal/core webflo/drupal-core-require-dev --with-dependencies
drush updatedb
drush cr

The composer.phar shows no errors but we are seeing an error during the updatedb

I have Drupal 8 installed and everything works fine. Now I want to use the MySql+php -program in the same environment. Is it possible to launch a program “something.php” from the Drupal-page and use it as separate program? Tried with no success. Any links to find help?

I have a requirement of being able to use one Drupal website as a 'master' as far as the admin side goes - for another site (or two) that have similar content / similar / same products .... but sites are using different ccTLD's. Primarily as a management tool for common admin functions across the same platform.

Is this possible / practicable or am I asking too much? I would value advice and opinion.

cheers