diff -aur cacti/install/index.php cacti-PHP7/install/index.php
--- cacti/install/index.php	2016-02-07 20:26:54.000000000 +0100
+++ cacti-PHP7/install/index.php	2016-02-24 22:33:10.713574142 +0100
@@ -63,7 +63,7 @@
 }
 
 function verify_php_extensions() {
-	$extensions = array("session", "sockets", "mysql", "xml");
+	$extensions = array("session", "sockets", "pdo_mysql", "xml");
 	$ok = true;
 	$missing_extension = "	<p style='font-family: Verdana, Arial; font-size: 16px; font-weight: bold; color: red;'>Error</p>
 							<p style='font-family: Verdana, Arial; font-size: 12px;'>The following PHP extensions are missing:</p><ul>";
diff -aur cacti/lib/adodb/adodb.inc.php cacti-PHP7/lib/adodb/adodb.inc.php
--- cacti/lib/adodb/adodb.inc.php	2010-08-21 17:03:22.000000000 +0200
+++ cacti-PHP7/lib/adodb/adodb.inc.php	2016-02-24 22:19:33.915880478 +0100
@@ -863,13 +863,13 @@
 		} 
 		
 		if ($this->_queryID === true) { // return simplified recordset for inserts/updates/deletes with lower overhead
-			$rs =& new ADORecordSet_empty();
+			$rs = new ADORecordSet_empty();
 			return $rs;
 		}
 		
 		// return real recordset from select statement
 		$rsclass = $this->rsPrefix.$this->databaseType;
-		$rs =& new $rsclass($this->_queryID,$this->fetchMode);
+		$rs = new $rsclass($this->_queryID,$this->fetchMode);
 		$rs->connection = &$this; // Pablo suggestion
 		$rs->Init();
 		if (is_array($sql)) $rs->sql = $sql[0];
@@ -1180,7 +1180,7 @@
 		
 		$arrayClass = $this->arrayClass;
 		
-		$rs2 =& new $arrayClass();
+		$rs2 = new $arrayClass();
 		$rs2->connection = &$this;
 		$rs2->sql = $rs->sql;
 		$rs2->dataProvider = $this->dataProvider;
@@ -1958,7 +1958,7 @@
 
 			$retarr = array();
 			while (!$rs->EOF) { //print_r($rs->fields);
-				$fld =& new ADOFieldObject();
+				$fld = new ADOFieldObject();
 				$fld->name = $rs->fields[0];
 				$fld->type = $rs->fields[1];
 				if (isset($rs->fields[3]) && $rs->fields[3]) {
@@ -3024,7 +3024,7 @@
 	function &FetchObject($isupper=true)
 	{
 		if (empty($this->_obj)) {
-			$this->_obj =& new ADOFetchObj();
+			$this->_obj = new ADOFetchObj();
 			$this->_names = array();
 			for ($i=0; $i <$this->_numOfFields; $i++) {
 				$f = $this->FetchField($i);
@@ -3589,7 +3589,7 @@
 				return $false;
 			}
 			
-			$obj =& new $cls();
+			$obj = new $cls();
 		}
 		
 		# constructor should not fail
@@ -3664,7 +3664,7 @@
 		@include_once(ADODB_DIR."/perf/perf-$drivername.inc.php");
 		$class = "Perf_$drivername";
 		if (!class_exists($class)) return $false;
-		$perf =& new $class($conn);
+		$perf = new $class($conn);
 		
 		return $perf;
 	}
@@ -3684,7 +3684,7 @@
 		}
 		include_once($path);
 		$class = "ADODB2_$drivername";
-		$dict =& new $class();
+		$dict = new $class();
 		$dict->dataProvider = $conn->dataProvider;
 		$dict->connection = &$conn;
 		$dict->upperName = strtoupper($drivername);
diff -aur cacti/lib/adodb/drivers/adodb-pdo.inc.php cacti-PHP7/lib/adodb/drivers/adodb-pdo.inc.php
--- cacti/lib/adodb/drivers/adodb-pdo.inc.php	2010-08-21 17:03:22.000000000 +0200
+++ cacti-PHP7/lib/adodb/drivers/adodb-pdo.inc.php	2016-02-24 22:20:42.780689777 +0100
@@ -43,16 +43,16 @@
 		$this->_connectionID = new PDO($argDSN, $argUsername, $argPassword);
 		if ($this->_connectionID) {
 			switch(ADODB_ASSOC_CASE){
-			case 0: $m = PDO_CASE_LOWER; break;
-			case 1: $m = PDO_CASE_UPPER; break;
+			case 0: $m = PDO::CASE_LOWER; break;
+			case 1: $m = PDO::CASE_UPPER; break;
 			default:
-			case 2: $m = PDO_CASE_NATURAL; break;
+			case 2: $m = PDO::CASE_NATURAL; break;
 			}
 			
-			//$this->_connectionID->setAttribute(PDO_ATTR_ERRMODE,PDO_ERRMODE_SILENT );
-			$this->_connectionID->setAttribute(PDO_ATTR_CASE,$m);
+			//$this->_connectionID->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_SILENT );
+			$this->_connectionID->setAttribute(PDO::ATTR_CASE,$m);
 			
-			//$this->_connectionID->setAttribute(PDO_ATTR_AUTOCOMMIT,true);
+			//$this->_connectionID->setAttribute(PDO::ATTR_AUTOCOMMIT,true);
 			
 			return true;
 		}
@@ -96,7 +96,7 @@
 		if ($this->transOff) return true; 
 		$this->transCnt += 1;
 		$this->_autocommit = false;
-		$this->_connectionID->setAttribute(PDO_ATTR_AUTOCOMMIT,false);
+		$this->_connectionID->setAttribute(PDO::ATTR_AUTOCOMMIT,false);
 		return $this->_connectionID->beginTransaction();
 	}
 	
@@ -108,7 +108,7 @@
 		$this->_autocommit = true;
 		
 		$ret = $this->_connectionID->commit();
-		$this->_connectionID->setAttribute(PDO_ATTR_AUTOCOMMIT,true);
+		$this->_connectionID->setAttribute(PDO::ATTR_AUTOCOMMIT,true);
 		return $ret;
 	}
 	
@@ -119,7 +119,7 @@
 		$this->_autocommit = true;
 		
 		$ret = $this->_connectionID->rollback();
-		$this->_connectionID->setAttribute(PDO_ATTR_AUTOCOMMIT,true);
+		$this->_connectionID->setAttribute(PDO::ATTR_AUTOCOMMIT,true);
 		return $ret;
 	}
 	
@@ -242,9 +242,9 @@
 		}
 		switch($mode) {
 		default:
-		case ADODB_FETCH_BOTH: $mode = PDO_FETCH_BOTH; break;
-		case ADODB_FETCH_NUM: $mode = PDO_FETCH_NUM; break;
-		case ADODB_FETCH_ASSOC:  $mode = PDO_FETCH_ASSOC; break;
+		case ADODB_FETCH_BOTH: $mode = PDO::FETCH_BOTH; break;
+		case ADODB_FETCH_NUM: $mode = PDO::FETCH_NUM; break;
+		case ADODB_FETCH_ASSOC:  $mode = PDO::FETCH_ASSOC; break;
 		}
 		$this->fetchMode = $mode;
 		
diff -aur cacti/lib/html_tree.php cacti-PHP7/lib/html_tree.php
--- cacti/lib/html_tree.php	2015-11-17 02:39:54.000000000 +0100
+++ cacti-PHP7/lib/html_tree.php	2016-02-24 22:24:00.738287850 +0100
@@ -510,7 +510,7 @@
 
 	$default_tree_id = read_graph_config_option('default_tree_id');
 
-	if (empty($default_tree_id)) {
+	if (empty($default_tree_id) && isset($_SESSION['sess_user_id'])) {
 		$user = db_fetch_row('SELECT * FROM user_auth WHERE id=' . $_SESSION['sess_user_id']);
 
 		if ($user['policy_trees'] == 1) {