To adjust the number of Recently Added Topics displayed on the index sidebar hook on IP.Board 3.1, a small file edit is required.Connect via FTP.Look in \admin\applications\forums\sources\classes\forums\3.1.2 / 3.1.1 :Edit class_forums.php, around line 2495, find...
$_topics = array_slice( $topicIDs, 0, 5 );
3.1.3 :Edit class_forums.php, around line 2350, find...
public function hooks_recentTopics( $topicCount=5, $output=true )
3.1.4 :Edit class_forums.php, around line 2346, find...
public function hooks_recentTopics( $topicCount=5, $output=true )
3.2.0 :Edit class_forums.php, around line 2346, find...
public function hooks_recentTopics( $topicCount=5, $output=true )
Adjust the 5 there to what you require (3 or 10 seems to be popular choices, although setting this too high can cause performance issues) and save, taking care not to disturb any other lines or the syntax.