diff --git a/ChangeLog b/ChangeLog
index 0d05ea7..e683497 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,11 +1,14 @@
-1.8.2 - Thursday 20 February 2026
+1.8.2 - Thursday 04 March 2026
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- Fixed: PHP 8.5 deprecation of using 'null' as an array key, switch to ''.
+- Fixed: PHP 8.5 deprecation of SplObjectStorage::contains(), detach(), and attach().
 - Fixed: PHP 8.4 deprecation of implicit nullable parameter types in ezcPersistentSaveHandler::saveInternal().
 - Fixed: PHP 8.4 deprecation of implicit nullable parameter types in ezcPersistentObjectIdProperty::__construct().
 - Fixed: PHP 8.4 deprecation of implicit nullable parameter types in ezcPersistentObjectDefinition::__construct().
 - Fixed: PHP 8.4 deprecation of implicit nullable parameter types in ezcPersistentSessionIdentityDecorator::__construct().
 - Fixed: PHP 8.4 deprecation of implicit nullable parameter types in ezcPersistentIdentity::__construct().
+- Fixed: PHP 8.3 deprecation of dynamic property creation.
 - Fixed: PHP 8.1 deprecation of non-covariant return types in ezcPersistentFindIterator::rewind(), current(), key(), next() and valid().
 - Fixed: PHP 8.1 deprecation of non-covariant return types in ezcPersistentIdentityFindIterator::next().
 - Fixed: PHP 8.1 deprecation of non-covariant return types in ezcPersistentRelationCollection::offsetSet(), exchangeArray(), setFlags() and append().
diff --git a/src/identity_maps/basic.php b/src/identity_maps/basic.php
index a2c3b6f..25d3bcb 100644
--- a/src/identity_maps/basic.php
+++ b/src/identity_maps/basic.php
@@ -466,7 +466,7 @@ public function addRelatedObject( $sourceObject, $relatedObject, $relationName =
         $relStore[$relId] = $relatedObject;
 
         // Store new reference
-        $this->identities[$relClass][$relId]->references->attach(
+        $this->identities[$relClass][$relId]->references->offsetSet(
             $relStore
         );
         
@@ -530,7 +530,7 @@ public function removeRelatedObject( $sourceObject, $relatedObject, $relationNam
         if ( isset( $srcIdentity->relatedObjects[$relationStoreName] ) )
         {
             unset( $srcIdentity->relatedObjects[$relationStoreName][$relId] );
-            $relIdentity->references->detach( $srcIdentity->relatedObjects[$relationStoreName] );
+            $relIdentity->references->offsetUnset( $srcIdentity->relatedObjects[$relationStoreName] );
         }
 
         foreach ( $srcIdentity->namedRelatedObjectSets as $setName => $rels )
@@ -538,7 +538,7 @@ public function removeRelatedObject( $sourceObject, $relatedObject, $relationNam
             if ( isset( $rels[$relId] ) && $rels[$relId] instanceof $relClass )
             {
                 unset( $srcIdentity->namedRelatedObjectSets[$setName][$relId] );
-                $relIdentity->references->detach(
+                $relIdentity->references->offsetUnset(
                     $srcIdentity->namedRelatedObjectSets[$setName]
                 );
             }
@@ -693,10 +693,10 @@ protected function removeReferences( ArrayObject $set )
             $def   = $this->definitionManager->fetchDefinition( $class );
             $state = $obj->getState();
             $id    = $state[$def->idProperty->propertyName];
-            
-            if ( $this->identities[$class][$id]->references->contains( $set ) )
+
+            if ( $this->identities[$class][$id]->references->offsetExists( $set ) )
             {
-                $this->identities[$class][$id]->references->detach( $set );
+                $this->identities[$class][$id]->references->offsetUnset( $set );
             }
         }
     }
diff --git a/src/persistent_session_instance.php b/src/persistent_session_instance.php
index 3e0cac8..a8a8374 100644
--- a/src/persistent_session_instance.php
+++ b/src/persistent_session_instance.php
@@ -9,9 +9,9 @@
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
- * 
+ *
  *   http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
@@ -54,7 +54,7 @@ class ezcPersistentSessionInstance
      * @see ezcPersistentSessionInstance::get()
      * @var string
      */
-    static private $defaultInstanceIdentifier = null;
+    static private $defaultInstanceIdentifier = '';
 
     /**
      * Holds the session instances.
@@ -79,9 +79,9 @@ class ezcPersistentSessionInstance
      * @param string $identifier
      * @return ezcPersistentSession
      */
-    public static function get( $identifier = null )
+    public static function get( $identifier = '' )
     {
-        if ( $identifier === null && self::$defaultInstanceIdentifier )
+        if ( $identifier === '' && self::$defaultInstanceIdentifier )
         {
             $identifier = self::$defaultInstanceIdentifier;
         }
@@ -115,9 +115,9 @@ public static function get( $identifier = null )
      * @param string $identifier the identifier of the database handler
      * @return void
      */
-    public static function set( ezcPersistentSessionFoundation $session, $identifier = null )
+    public static function set( ezcPersistentSessionFoundation $session, $identifier = '' )
     {
-        if ( $identifier === null )
+        if ( $identifier === '' )
         {
             $identifier = self::$defaultInstanceIdentifier;
         }
@@ -157,7 +157,7 @@ public static function resetDefault()
      */
     public static function reset()
     {
-        self::$defaultInstanceIdentifier = null;
+        self::$defaultInstanceIdentifier = '';
         self::$instances = array();
     }
 }