diff --git a/config/psalm.xml b/config/psalm.xml
index 957b02d..cda5bbe 100644
--- a/config/psalm.xml
+++ b/config/psalm.xml
@@ -8,6 +8,7 @@
         findUnusedBaselineEntry="false"
         findUnusedCode="false"
         errorLevel="1"
+        phpVersion="8.1"
 >
     <projectFiles>
         <directory name="../src"/>
diff --git a/src/Model/ModelRegistry.php b/src/Model/ModelRegistry.php
index 09a7947..68828f5 100644
--- a/src/Model/ModelRegistry.php
+++ b/src/Model/ModelRegistry.php
@@ -98,9 +98,6 @@ public function referencedModels(): array
         return $this->referencedModels;
     }
 
-    /**
-     * @psalm-pure
-     */
     private function definitionKey(Definition $definition): string
     {
         $exampleObject = $definition->exampleObject();
diff --git a/src/Resolver/DefinitionName.php b/src/Resolver/DefinitionName.php
index 466965d..c2b5cc1 100644
--- a/src/Resolver/DefinitionName.php
+++ b/src/Resolver/DefinitionName.php
@@ -37,8 +37,6 @@ private static function getNameForClass(string $class): string
 
     /**
      * @param string[] $groups
-     *
-     * @psalm-pure
      */
     private static function getGroupsSuffix(array $groups): string
     {