Error in feed upgrade

2018-10-09 10:09:01,853 [ActiveMQ Session Task-1] ERROR SqlExceptionHelper  - Incorrect string value: '\xF0\x9F\x99\x82" ...' for column 'f_content' at row 1
2018-10-09 10:09:01,854 [ActiveMQ Session Task-1] ERROR OLATUpgrade_12_5_3  - OLAT::ERROR ^%^ N1-E2 ^%^ org.olat.upgrade ^%^ n/a ^%^ n/a ^%^ n/a ^%^ n/a ^%^
>>>stack of 1.cause::javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not execute statement
-> at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:149)
   at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:157)
   at org.hibernate.query.internal.AbstractProducedQuery.list(AbstractProducedQuery.java:1423)
   at org.hibernate.query.Query.getResultList(Query.java:146)
   at org.olat.modules.webFeed.manager.ItemDAO.loadItemByGuid(ItemDAO.java:147)
   at org.olat.modules.webFeed.manager.FeedManagerImpl.saveExternalItems(FeedManagerImpl.java:501)
   at org.olat.modules.webFeed.manager.FeedManagerImpl.importFeedFromXML(FeedManagerImpl.java:845)
   at org.olat.upgrade.OLATUpgrade_12_5_3.upgradeBlogXmlToDb(OLATUpgrade_12_5_3.java:96)
   at org.olat.upgrade.OLATUpgrade_12_5_3.doPostSystemInitUpgrade(OLATUpgrade_12_5_3.java:74)
   at org.olat.upgrade.UpgradeManagerImpl.doPostSystemInitUpgrades(UpgradeManagerImpl.java:78)
   at org.olat.upgrade.UpgradeManager.event(UpgradeManager.java:204)
>>>stack of 2.cause::org.hibernate.exception.GenericJDBCException: could not execute statement
-> at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:47)
   at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:111)
   at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:97)
   at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:178)
   at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3203)
   at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:3076)
   at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3457)
   at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:145)
   at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:600)
   at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:474)
   at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337)
>>>stack of 3.cause::java.sql.SQLException: Incorrect string value: '\xF0\x9F\x99\x82" ...' for column 'f_content' at row 1
-> at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:965)
   at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973)
   at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909)
   at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527)
   at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680)
   at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2484)
   at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1858)
   at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2079)
   at com.mysql.jdbc.PreparedStatement.executeUpdateInternal(PreparedStatement.java:2013)
   at com.mysql.jdbc.PreparedStatement.executeLargeUpdate(PreparedStatement.java:5104)
   at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1998)