The Events Calendar: Override the default iCal export to be more than 30 upcoming events (only affects List, Map, and Photo views).

functions.php

<?php

/**
 * The Events Calendar: Override the default iCal export to be more than 30
 * upcoming events (only affects List, Map, and Photo views).
 * 
 * The iCal exports for Month, Week, and Day views match their actual displays.
 *
 * @link https://gist.github.com/cliffordp/0da84c8596a04af3e7409afa62521273
 *
 * @return int
 */
add_filter( 'tribe_ical_feed_posts_per_page', function(){
	return 1000;
});