Don't link to the oC forum

Signed-off-by: Joas Schilling <coding@schilljs.com>

core/js/update.js

@@ -72,7 +72,7 @@
 				var span = $('<span>')
 					.addClass('bold');
 				if(message === 'Exception: Updates between multiple major versions and downgrades are unsupported.') {
-					span.append(t('core', 'The update was unsuccessful. For more information <a href="{url}">check our forum post</a> covering this issue.', {'url': 'https://forum.owncloud.org/viewtopic.php?f=17&t=32087'}));
+					span.append(t('core', 'The update was unsuccessful. For more information <a href="{url}">check our forum post</a> covering this issue.', {'url': 'https://help.nextcloud.com/t/updates-between-multiple-major-versions-are-unsupported/7094'}));
 				} else {
 					span.append(t('core', 'The update was unsuccessful. ' +
 						'Please report this issue to the ' +