diff --git a/stubs/smbclient.stub b/stubs/smbclient.stub
index 97e0a0e..d12ed75 100644
--- a/stubs/smbclient.stub
+++ b/stubs/smbclient.stub
@@ -25,7 +25,7 @@ function smbclient_state_new() {
 /**
  * @param resource $state
  */
-function smbclient_state_init($state, string $workgroup = null, string $user = null, string $password = null): bool {
+function smbclient_state_init($state, ?string $workgroup = null, ?string $user = null, ?string $password = null): bool {
 }
 
 /**
@@ -61,7 +61,7 @@ function smbclient_option_set($state, int $option, $value) {
  * @param resource $state
  * @return bool
  */
-function smbclient_client_protocols($state, string $minproto = null, string $maxproto = null): bool {
+function smbclient_client_protocols($state, ?string $minproto = null, ?string $maxproto = null): bool {
 }
 
 #endif