--- a/heuristics/historyHeuristics.php
+++ b/heuristics/historyHeuristics.php
@@ -23,8 +23,8 @@
 	global $agencyTransactions;
 	if (!$agencyTransactions[$agencyName]) {
 		$query = 'select count(*) from contractnotice where agencyName = "' . $agencyName . '"';
-		$result = mysql_query($query);
-		$r = mysql_fetch_array($result, MYSQL_BOTH);
+    $result = $conn->query($query);
+    $r = $result->fetch(PDO::FETCH_BOTH);
 		$agencyTransactions[$agencyName] = $r[0];
 	}
 	return $agencyTransactions[$agencyName];
@@ -52,8 +52,8 @@
 	global $averageAgencyTransactions, $stddevAgencyTransactions;
 	$query = "select avg(count), STDDEV(count) from (select count(*) as count
                 from contractnotice group by agencyName) as a;";
-	$result = mysql_query($query);
-	$r = mysql_fetch_array($result, MYSQL_BOTH);
+    $result = $conn->query($query);
+    $r = $result->fetch(PDO::FETCH_BOTH);
 	$averageAgencyTransactions = $r[0];
 	$stddevAgencyTransactions = $r[1];
 }
@@ -82,16 +82,16 @@
 	if ($supplierABN != 0 && $supplierABN != "") {
 		if (!$supplierTransactions[$supplierABN]) {
 			$query = 'select count(*) from contractnotice where supplierABN = "' . $supplierABN . '"';
-			$result = mysql_query($query);
-			$r = mysql_fetch_array($result, MYSQL_BOTH);
+			    $result = $conn->query($query);
+    $r = $result->fetch(PDO::FETCH_BOTH);
 			$supplierTransactions[$supplierABN] = $r[0];
 		}
 		return $supplierTransactions[$supplierABN];
 	}
 	if (!$supplierTransactions[$supplierName]) {
 		$query = 'select count(*) from contractnotice where supplierName = "' . $supplierName . '"';
-		$result = mysql_query($query);
-		$r = mysql_fetch_array($result, MYSQL_BOTH);
+    $result = $conn->query($query);
+    $r = $result->fetch(PDO::FETCH_BOTH);
 		$supplierTransactions[$supplierName] = $r[0];
 	}
 	return $supplierTransactions[$supplierName];
@@ -118,8 +118,8 @@
 {
 	global $averageSupplierTransactions, $stddevSupplierTransactions;
 	$query = 'select avg(count), stddev(count) from (select IF(supplierABN != "",supplierABN,supplierName) as supplierID, count(*) as count from contractnotice group by supplierID) as a;';
-	$result = mysql_query($query);
-	$r = mysql_fetch_array($result, MYSQL_BOTH);
+    $result = $conn->query($query);
+    $r = $result->fetch(PDO::FETCH_BOTH);
 	$averageSupplierTransactions = $r[0];
 	$stddevSupplierTransactions = $r[1];
 }