Give users a new level after x successful payments at a specific previous level - based on https://gist.github.com/messica/7d3436b18adf1b18116d#file-my_pmpro_after_change_membership_level-php-L14-L17

gistfile1.txt

<?php
/*
 * Give users a new level after x successful payments at another level.
 */
function my_pmpro_after_change_membership_level($level_id, $user_id, $cancel_level)
{
	global $wpdb;
  
	// change number of payments here
	$payments = 10;
  
        // change to the ID of the level the users need to make payments at
	$previous_level = 2;
  
        // get old level
  	$order = new MemberOrder();
	$order->getLastMemberOrder($user_id);
	$old_level_id = $order->membership_id;
	
	// are they expiring?
	if( $level_id == 0 && $cancel_level == $previous_level )
	{
		// count successful orders for this level
		$sql   = "SELECT COUNT(id) FROM $wpdb->pmpro_membership_orders WHERE user_id=$user_id AND status='success' AND membership_id=$old_level_id";
		$count = $wpdb->query($sql);
		// give them the new level if they have enough payments
		if($count >= $payments)
			pmpro_changeMembershipLevel($old_level_id, $user_id);
	}
}
add_action("pmpro_after_change_membership_level", "my_pmpro_after_change_membership_level", 10, 3);