function llms_update_450_migrate_events_open_sessions() {

	$limit = 200;
	$skip  = get_transient( 'llms_450_skipper_events_open_sessions' );
	if ( ! $skip ) {
		$skip = 0;
	}
	set_transient( 'llms_450_skipper_events_open_sessions', $skip + $limit, DAY_IN_SECONDS );

	global $wpdb;
	$maybe_open_sessions = $wpdb->get_results(
		$wpdb->prepare(
			"SELECT id, actor_id, object_id
			FROM {$wpdb->prefix}lifterlms_events
			WHERE event_type='session'
			AND event_action='start'
			ORDER BY id ASC
			LIMIT %d, %d
		",
			$skip,
			$limit
		)
	); // db call ok; no-cache ok.

	// Finished.
	if ( empty( $maybe_open_sessions ) ) {
		set_transient( 'llms_update_450_migrate_events_open_sessions', 'complete', DAY_IN_SECONDS );
		return false;
	}

	$insert = '';
	foreach ( $maybe_open_sessions as $maybe_open_session ) {
		// Create an event instance so to pass it to the `LLMS_Sessions::instance()->is_session_open()` util.
		$start = new LLMS_Event( $maybe_open_session->id );

		// Set the only useful properties, without the need to save them from the db.
		$start->set( 'actor_id', $maybe_open_session->actor_id, false );
		$start->set( 'object_id', $maybe_open_session->object_id, false );

		if ( LLMS_Sessions::instance()->is_session_open( $start ) ) {
			if ( ! empty( $insert ) ) {
				$insert .= ', ';
			}
			$insert .= $wpdb->prepare( '(%s)', $maybe_open_session->id );
		}
	}

	// Add the open sessions to the new table.
	if ( ! empty( $insert ) ) {
		$wpdb->query(
			"INSERT INTO {$wpdb->prefix}lifterlms_events_open_sessions ( `event_id` ) VALUES " . $insert . ';' // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- Values are prepared above.
		); // db call ok; no-cache ok.
	}

	// Needs to run again.
	return true;
}