I checked it and could reporoduce the error
Unknown column 'places' in 'field list' if you uninstalled JEM 2.3.6 and reinstallted JEM 4 after the update to Joomla 4.
I had a look at the DB and you need some adjustemnts:
In phpmyadmin execute the following comand list (and: "YOUR_PREFIX" is your specific prefix for the tables in you database :woohoo: )
Code:
ALTER TABLE `YOUR_PREFIX_jem_attachments` CHANGE `added` `added` DATETIME NULL DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `description` `description` mediumtext DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `meta_keywords` `meta_keywords` text DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `meta_description` `meta_description` text DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `checked_out_time` `checked_out_time` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `checked_out_time` `checked_out_time` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `note` `note` varchar(255) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `language` `language` varchar(7) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `created_time` `created_time` datetime NOT NULL DEFAULT current_timestamp();
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `path` `path` varchar(255) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `metadata` `metadata` varchar(2048) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `modified_time` `modified_time` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` CHANGE `email` `email` varchar(200) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_categories` ADD `emailacljl` tinyint(4) NOT NULL DEFAULT 0;
ALTER TABLE `YOUR_PREFIX_jem_cats_event_relations` CHANGE `ordering` `ordering` tinyint(11) NOT NULL DEFAULT 0
UPDATE YOUR_PREFIX_jem_config SET value='H:i' WHERE `value`='%H:%M';
UPDATE YOUR_PREFIX_jem_config SET value='H' WHERE `value`='%H';
UPDATE YOUR_PREFIX_jem_config SET value='jpg,gif,png,webp' WHERE `value`='jpg,gif,png';
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `modified` `modified` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `created` `created` datetime NOT NULL DEFAULT current_timestamp();
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `meta_keywords` `meta_keywords` varchar(200) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `meta_description` `meta_description` varchar(255) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `checked_out_time` `checked_out_time` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_events` ADD `reservedplaces` int(11) NOT NULL DEFAULT 1 AFTER `maxplaces`;
ALTER TABLE `YOUR_PREFIX_jem_events` ADD `maxbookeduser` int(11) NOT NULL DEFAULT 1 AFTER `maxplaces`;
ALTER TABLE `YOUR_PREFIX_jem_events` ADD `minbookeduser` int(11) NOT NULL DEFAULT 0 AFTER `maxplaces`;
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `attribs` `attribs` varchar(5120) NOT NULL DEFAULT '''';
ALTER TABLE YOUR_PREFIX_jem_events MODIFY author_ip varchar(39);
ALTER TABLE `YOUR_PREFIX_jem_events` CHANGE `language` `language` char(7) NOT NULL DEFAULT '''';
ALTER TABLE `YOUR_PREFIX_jem_groups` CHANGE `description` `description` mediumtext DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_groups` CHANGE `checked_out_time` `checked_out_time` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_register` ADD `places` int(11) NOT NULL DEFAULT 1 AFTER `uid`;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `locdescription` `locdescription` mediumtext DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `meta_keywords` `meta_keywords` text DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `meta_description` `meta_description` text DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `created` `created` datetime NOT NULL DEFAULT current_timestamp();
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `modified` `modified` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `checked_out_time` `checked_out_time` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `publish_up` `publish_up` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `publish_down` `publish_down` datetime DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `attribs` `attribs` varchar(5120) DEFAULT NULL;
ALTER TABLE `YOUR_PREFIX_jem_venues` CHANGE `language` `language` char(7) DEFAULT NULL;
UPDATE YOUR_PREFIX_jem_categories SET `checked_out_time` = NULL WHERE `checked_out_time`='0000-00-00 00:00:00';
UPDATE YOUR_PREFIX_jem_categories SET `modified_time` = NULL WHERE `modified_time`='0000-00-00 00:00:00';
UPDATE YOUR_PREFIX_jem_events SET `modified` = NULL WHERE `modified`='0000-00-00 00:00:00';
UPDATE YOUR_PREFIX_jem_events SET `checked_out_time` = NULL WHERE `checked_out_time`='0000-00-00 00:00:00';
I hope I did not miss anything.
