I upgraded using the SSH command line from 2.13 t. 2.14 just now. The system seems to work just fine but there is an error in the log:
mautic.NOTICE: Doctrine\DBAL\Exception\DriverException: An exception occurred while executing 'ALTER TABLE mauci_lead_event_log DROP FOREIGN KEY FK_CFC0FC6355458D': Can't DROP FOREIGN KEY
FK_CFC0FC6355458D; check that it exists (uncaught exception) at /home/fncvoxvg/public_html/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/AbstractMySQLDriver.php line 115 while running console command
doctrine:migrations:migrate[] []