Facing an issue while upgrading from drupal 8.4 to 8.6.
The website encountered an unexpected error. Please try again later.
SymfonyComponentDependencyInjectionExceptionServiceNotFoundException: You have requested a non-existent service “access_check.db_update”. in SymfonyComponentDependencyInjectionContainerBuilder->getDefinition() (line 1053 of vendorsymfonydependency-injectionContainerBuilder.php).
I have unzip a fresh drupal 8.6 files and then added 8.4 custom themes and module files. Then i have connected drupal 8.6 to my drupal 8.4 database in settings.php and after that have put update.php url in browser then i got the above error message.