diff --git a/src/Dibi/Drivers/MySqliDriver.php b/src/Dibi/Drivers/MySqliDriver.php
index 0b7c6826..5ee7c27b 100644
--- a/src/Dibi/Drivers/MySqliDriver.php
+++ b/src/Dibi/Drivers/MySqliDriver.php
@@ -106,7 +106,7 @@ class MySqliDriver implements Dibi\Driver, Dibi\ResultDriver
 					}
 				}
 			}
-			@mysqli_real_connect($this->connection, (empty($config['persistent']) ? '' : 'p:') . $config['host'], $config['username'], $config['password'], $config['database'], $config['port'], $config['socket'], $config['flags']); // intentionally @
+			@mysqli_real_connect($this->connection, (empty($config['persistent']) ? '' : 'p:') . $config['host'], $config['username'], $config['password'], $config['database'] ?? '', $config['port'] ?? 0, $config['socket'], $config['flags'] ?? 0); // intentionally @
 
 			if ($errno = mysqli_connect_errno()) {
 				throw new Dibi\DriverException(mysqli_connect_error(), $errno);
diff --git a/src/Dibi/Drivers/OdbcDriver.php b/src/Dibi/Drivers/OdbcDriver.php
index facb98e2..65ca0c01 100644
--- a/src/Dibi/Drivers/OdbcDriver.php
+++ b/src/Dibi/Drivers/OdbcDriver.php
@@ -69,9 +69,9 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 			];
 
 			if (empty($config['persistent'])) {
-				$this->connection = @odbc_connect($config['dsn'], $config['username'], $config['password']); // intentionally @
+				$this->connection = @odbc_connect($config['dsn'], $config['username'] ?? '', $config['password'] ?? ''); // intentionally @
 			} else {
-				$this->connection = @odbc_pconnect($config['dsn'], $config['username'], $config['password']); // intentionally @
+				$this->connection = @odbc_pconnect($config['dsn'], $config['username'] ?? '', $config['password'] ?? ''); // intentionally @
 			}
 		}
 
@@ -134,7 +134,7 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	 */
 	public function begin(string $savepoint = NULL): void
 	{
-		if (!odbc_autocommit($this->connection, FALSE)) {
+		if (!odbc_autocommit($this->connection, 0/*FALSE*/)) {
 			throw new Dibi\DriverException(odbc_errormsg($this->connection) . ' ' . odbc_error($this->connection));
 		}
 	}
@@ -149,7 +149,7 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 		if (!odbc_commit($this->connection)) {
 			throw new Dibi\DriverException(odbc_errormsg($this->connection) . ' ' . odbc_error($this->connection));
 		}
-		odbc_autocommit($this->connection, TRUE);
+		odbc_autocommit($this->connection, 1/*TRUE*/);
 	}
 
 
@@ -162,7 +162,7 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 		if (!odbc_rollback($this->connection)) {
 			throw new Dibi\DriverException(odbc_errormsg($this->connection) . ' ' . odbc_error($this->connection));
 		}
-		odbc_autocommit($this->connection, TRUE);
+		odbc_autocommit($this->connection, 1/*TRUE*/);
 	}
 
 
diff --git a/src/Dibi/Drivers/PdoDriver.php b/src/Dibi/Drivers/PdoDriver.php
index d1f2c5d7..b11f1fe6 100644
--- a/src/Dibi/Drivers/PdoDriver.php
+++ b/src/Dibi/Drivers/PdoDriver.php
@@ -80,8 +80,7 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 		}
 
 		$this->driverName = $this->connection->getAttribute(PDO::ATTR_DRIVER_NAME);
-		$this->serverVersion = $config['version']
-			?? @$this->connection->getAttribute(PDO::ATTR_SERVER_VERSION); // @ - may be not supported
+		$this->serverVersion = (string) ($config['version'] ?? @$this->connection->getAttribute(PDO::ATTR_SERVER_VERSION)); // @ - may be not supported
 	}
 
 
diff --git a/src/Dibi/Drivers/SqlsrvDriver.php b/src/Dibi/Drivers/SqlsrvDriver.php
index bb795c48..1c292bca 100644
--- a/src/Dibi/Drivers/SqlsrvDriver.php
+++ b/src/Dibi/Drivers/SqlsrvDriver.php
@@ -137,7 +137,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 		$res = sqlsrv_query($this->connection, 'SELECT SCOPE_IDENTITY()');
 		if (is_resource($res)) {
 			$row = sqlsrv_fetch_array($res, SQLSRV_FETCH_NUMERIC);
-			return $row[0];
+			return (int) $row[0];
 		}
 		return NULL;
 	}
diff --git a/tests/dibi/bootstrap.php b/tests/dibi/bootstrap.php
index 9f7217af..254b884f 100644
--- a/tests/dibi/bootstrap.php
+++ b/tests/dibi/bootstrap.php
@@ -70,7 +70,7 @@ function reformat($s)
 function num($n)
 {
 	global $config;
-	if (substr(@$config['dsn'], 0, 5) === 'odbc:' || $config['driver'] === 'sqlite') {
+	if (substr($config['dsn'] ?? '', 0, 5) === 'odbc:' || $config['driver'] === 'sqlite') {
 		$n = is_float($n) ? "$n.0" : (string) $n;
 	}
 	return $n;