I have a problem. I change charset for showing smiles in nextcloud talk, but after this I get this error in journal nextcloud (loading index page). smileys is working 
Doctrine\DBAL\Exception\DriverException: An exception occurred while executing ‘SELECT * FROM oc_comments WHERE (message COLLATE UTF8_general_ci LIKE ?) AND (object_type = ?) ORDER BY creation_timestamp DESC, id DESC LIMIT 100’ with params ["%%", “files”]: SQLSTATE[42000]: Syntax error or access violation: 1253 COLLATION ‘UTF8_general_ci’ is not valid for CHARACTER SET ‘utf8mb4’
/var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php - line 184:
Doctrine\DBAL\Driver\AbstractMySQLDriver->convertException("An exceptio ... '", Doctrine\DBA ... ]})
/var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php - line 158:
Doctrine\DBAL\DBALException::wrapException(Doctrine\DBA ... {}, Doctrine\DBA ... ]}, "An exceptio ... '")
/var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php - line 938:
Doctrine\DBAL\DBALException::driverExceptionDuringQuery(Doctrine\DBA ... {}, Doctrine\DBA ... ]}, "SELECT * FR ... 0", { 1: "%%",2: "files"})
/var/www/nextcloud/lib/private/DB/Connection.php - line 195:
Doctrine\DBAL\Connection->executeQuery("SELECT * FR ... 0", [ "%%","files"], [ 2,2], null)
/var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Query/QueryBuilder.php - line 219:
OC\DB\Connection->executeQuery("SELECT * FR ... 0", { dcValue1: ... "}, { dcValue1: 2,dcValue2: 2})
/var/www/nextcloud/lib/private/DB/QueryBuilder/QueryBuilder.php - line 214:
Doctrine\DBAL\Query\QueryBuilder->execute()
/var/www/nextcloud/lib/private/Comments/Manager.php - line 543:
OC\DB\QueryBuilder\QueryBuilder->execute()
/var/www/nextcloud/apps/recommendations/lib/Service/RecentlyCommentedFilesSource.php - line 89:
OC\Comments\Manager->search("", "files", "", "", 0, 100)
/var/www/nextcloud/apps/recommendations/lib/Service/RecentlyCommentedFilesSource.php - line 124:
OCA\Recommendations\Service\RecentlyCommentedFilesSource->getCommentsPage(0, 100)
<<closure>>
OCA\Recommendations\Service\RecentlyCommentedFilesSource->getAllCommentedFiles(OC\User\User {})
/var/www/nextcloud/apps/recommendations/lib/Service/RecentlyCommentedFilesSource.php - line 164:
iterator_to_array(Generator {})
/var/www/nextcloud/apps/recommendations/lib/Service/RecommendationService.php - line 91:
OCA\Recommendations\Service\RecentlyCommentedFilesSource->getMostRecentRecommendation(OC\User\User {}, 6)
<<closure>>
OCA\Recommendations\Service\RecommendationService->OCA\Recommendations\Service\{closure}("*** sensiti ... *")
/var/www/nextcloud/apps/recommendations/lib/Service/RecommendationService.php - line 92:
array_reduce([ "*** sensi ... }], Closure {}, "*** sensiti ... *")
/var/www/nextcloud/apps/recommendations/lib/Controller/RecommendationController.php - line 63:
OCA\Recommendations\Service\RecommendationService->getRecommendations(OC\User\User {})
/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 166:
OCA\Recommendations\Controller\RecommendationController->index()
/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 99:
OC\AppFramework\Http\Dispatcher->executeController(OCA\Recommen ... {}, "index")
/var/www/nextcloud/lib/private/AppFramework/App.php - line 126:
OC\AppFramework\Http\Dispatcher->dispatch(OCA\Recommen ... {}, "index")
/var/www/nextcloud/lib/private/AppFramework/Routing/RouteActionHandler.php - line 47:
OC\AppFramework\App::main("OCA\\Recomm ... r", "index", OC\AppFramew ... {}, { _route: "r ... "})
<<closure>>
OC\AppFramework\Routing\RouteActionHandler->__invoke({ _route: "r ... "})
/var/www/nextcloud/lib/private/Route/Router.php - line 297:
call_user_func(OC\AppFramew ... {}, { _route: "r ... "})
/var/www/nextcloud/lib/base.php - line 975:
OC\Route\Router->match("/apps/recom ... s")
/var/www/nextcloud/index.php - line 42:
OC::handleRequest()
ЗапротоколированоDoctrine\DBAL\Driver\PDOException: SQLSTATE[42000]: Syntax error or access violation: 1253 COLLATION ‘UTF8_general_ci’ is not valid for CHARACTER SET ‘utf8mb4’
/var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php - line 930:
Doctrine\DBAL\Driver\PDOStatement->execute()
/var/www/nextcloud/lib/private/DB/Connection.php - line 195:
Doctrine\DBAL\Connection->executeQuery("SELECT * FR ... 0", [ "%%","files"], [ 2,2], null)
/var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Query/QueryBuilder.php - line 219:
OC\DB\Connection->executeQuery("SELECT * FR ... 0", { dcValue1: ... "}, { dcValue1: 2,dcValue2: 2})
/var/www/nextcloud/lib/private/DB/QueryBuilder/QueryBuilder.php - line 214:
Doctrine\DBAL\Query\QueryBuilder->execute()
/var/www/nextcloud/lib/private/Comments/Manager.php - line 543:
OC\DB\QueryBuilder\QueryBuilder->execute()
/var/www/nextcloud/apps/recommendations/lib/Service/RecentlyCommentedFilesSource.php - line 89:
OC\Comments\Manager->search("", "files", "", "", 0, 100)
/var/www/nextcloud/apps/recommendations/lib/Service/RecentlyCommentedFilesSource.php - line 124:
OCA\Recommendations\Service\RecentlyCommentedFilesSource->getCommentsPage(0, 100)
<<closure>>
OCA\Recommendations\Service\RecentlyCommentedFilesSource->getAllCommentedFiles(OC\User\User {})
/var/www/nextcloud/apps/recommendations/lib/Service/RecentlyCommentedFilesSource.php - line 164:
iterator_to_array(Generator {})
/var/www/nextcloud/apps/recommendations/lib/Service/RecommendationService.php - line 91:
OCA\Recommendations\Service\RecentlyCommentedFilesSource->getMostRecentRecommendation(OC\User\User {}, 6)
<<closure>>
OCA\Recommendations\Service\RecommendationService->OCA\Recommendations\Service\{closure}("*** sensiti ... *")
/var/www/nextcloud/apps/recommendations/lib/Service/RecommendationService.php - line 92:
array_reduce([ "*** sensi ... }], Closure {}, "*** sensiti ... *")
/var/www/nextcloud/apps/recommendations/lib/Controller/RecommendationController.php - line 63:
OCA\Recommendations\Service\RecommendationService->getRecommendations(OC\User\User {})
/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 166:
OCA\Recommendations\Controller\RecommendationController->index()
/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 99:
OC\AppFramework\Http\Dispatcher->executeController(OCA\Recommen ... {}, "index")
/var/www/nextcloud/lib/private/AppFramework/App.php - line 126:
OC\AppFramework\Http\Dispatcher->dispatch(OCA\Recommen ... {}, "index")
/var/www/nextcloud/lib/private/AppFramework/Routing/RouteActionHandler.php - line 47:
OC\AppFramework\App::main("OCA\\Recomm ... r", "index", OC\AppFramew ... {}, { _route: "r ... "})
<<closure>>
OC\AppFramework\Routing\RouteActionHandler->__invoke({ _route: "r ... "})
/var/www/nextcloud/lib/private/Route/Router.php - line 297:
call_user_func(OC\AppFramew ... {}, { _route: "r ... "})
/var/www/nextcloud/lib/base.php - line 975:
OC\Route\Router->match("/apps/recom ... s")
/var/www/nextcloud/index.php - line 42:
OC::handleRequest()