Eventbrite API change: temp fix - remove when no longer needed - can be added to the theme's functions.php file etc

temp-eb-fix.php

/**
 * Temporary solution to a problem where the tickets form does not show, due to a recent
 * Eventbrite API change.
 * 
 * @param  string $html
 * @param  int    $event_id
 * @param  int    $post_id
 * @return string
 */
function temp_fix_37178( $html, $event_id, $post_id ) {
	$api = Tribe__Events__Tickets__Eventbrite__API::instance();
	$event = $api->get_event( $post_id );
	
	if ( ! empty( $html ) ) return $html;
	if ( 'live' !== $event->status ) return $html;

	$iframe_url = ( is_ssl() ? 'https://' : 'http://' ) . 'www.eventbrite.com/tickets-external?eid=%s&ref=etckt&v=2';
	$iframe_url = apply_filters( 'tribe_events_eb_iframe_url', sprintf( $iframe_url, $event_id ) );

	return sprintf(
		'<div class="eventbrite-ticket-embed" style="width:100%%;text-align:left">
			<iframe id="eventbrite-tickets-%1$s" src="%2$s" style="height:200px;width:100%%;overflow:auto;"></iframe>
			<div style="font-family:Helvetica, Arial;font-size:10px;padding:5px 0 5px;margin:2px;width:100%%;text-align:left">
				<a target="_blank" href="http://www.eventbrite.com/features?ref=etckt" style="color:#ddd;text-decoration:none">Event registration</a>
				<span style="color:#ddd"> powered by </span>
				<a target="_blank" href="http://www.eventbrite.com?ref=etckt" style="color:#ddd;text-decoration:none">Eventbrite</a>
			</div>
		</div>', $event_id, $iframe_url
	);
}

add_filter( 'tribe_events_eb_iframe_html', 'temp_fix_37178', 10, 3 );

Note: this should allow the ticket form for imported events to display - it does not solve a related issue impeding the ability to make changes via the local event editor.