Fix PHP deprecation warnings (#9616)

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
 - OAuth: Support standard authentication with short-living password received with OIDC token (#9530)
+- Fix PHP deprecation warnings (#9616)
 
 ## Release 1.6.9
 

program/lib/Roundcube/rcube.php

@@ -942,7 +942,8 @@ class rcube
      */
     public function decrypt($cipher, $key = 'des_key', $base64 = true)
     {
-        if (strlen($cipher) == 0) {
+        // @phpstan-ignore-next-line
+        if (!is_string($cipher) || !strlen($cipher)) {
             return false;
         }
 

program/lib/Roundcube/rcube_imap_generic.php

@@ -676,7 +676,7 @@ class rcube_imap_generic
                 $gssapicontext->acquireCredentials($ccache);
 
                 $token   = '';
-                $success = $gssapicontext->initSecContext($this->prefs['gssapi_context'], null, null, null, $token);
+                $success = $gssapicontext->initSecContext($this->prefs['gssapi_context'], '', 0, 0, $token);
                 $token   = base64_encode($token);
             }
             catch (Exception $e) {