diff --git a/boot.php b/boot.php
index b8705fdf1..eb04732c5 100644
--- a/boot.php
+++ b/boot.php
@@ -534,39 +534,6 @@ function is_site_admin()
 	return local_user() && $admin_email && in_array(defaults($a->user, 'email', ''), $adminlist);
 }
 
-/**
- * @brief Returns querystring as string from a mapped array.
- *
- * @param array  $params mapped array with query parameters
- * @param string $name   of parameter, default null
- *
- * @return string
- */
-function build_querystring($params, $name = null)
-{
-	$ret = "";
-	foreach ($params as $key => $val) {
-		if (is_array($val)) {
-			/// @TODO maybe not compare against null, use is_null()
-			if ($name == null) {
-				$ret .= build_querystring($val, $key);
-			} else {
-				$ret .= build_querystring($val, $name . "[$key]");
-			}
-		} else {
-			$val = urlencode($val);
-			/// @TODO maybe not compare against null, use is_null()
-			if ($name != null) {
-				/// @TODO two string concated, can be merged to one
-				$ret .= $name . "[$key]" . "=$val&";
-			} else {
-				$ret .= "$key=$val&";
-			}
-		}
-	}
-	return $ret;
-}
-
 function explode_querystring($query)
 {
 	$arg_st = strpos($query, '?');
diff --git a/mod/network.php b/mod/network.php
index c8786b2f7..009f70b60 100644
--- a/mod/network.php
+++ b/mod/network.php
@@ -140,7 +140,7 @@ function network_init(App $a)
 
 		if ($remember_tab) {
 			$net_args = array_merge($query_array, $net_args);
-			$net_queries = build_querystring($net_args);
+			$net_queries = http_build_query($net_args);
 
 			$redir_url = ($net_queries ? $net_baseurl . '?' . $net_queries : $net_baseurl);