Updates between multiple major versions are unsupported

nickvergessen · October 10, 2019, 7:56am

Set the read only flag in your config:

nextcloud/server/blob/master/config/config.sample.php#L718-L728


/**
 * In certain environments it is desired to have a read-only configuration file.
 * When this switch is set to ``true`` Nextcloud will not verify whether the
 * configuration is writable. However, it will not be possible to configure
 * all options via the Web interface. Furthermore, when updating Nextcloud
 * it is required to make the configuration file writable again for the update
 * process.
 *
 * Defaults to ``false``
 */
'config_is_read_only' => false,