diff --git a/composer.json b/composer.json
index 58cc2c0..89cf517 100644
--- a/composer.json
+++ b/composer.json
@@ -7,10 +7,8 @@
         "php": "^8.0",
         "ext-curl": "*",
         "ext-json": "*",
-        "netresearch/jsonmapper": "^4.2",
-        "monolog/monolog": "^2.0|^3.0"
-    },
-    "suggest": {
+        "netresearch/jsonmapper": "^4.2|^5.0",
+        "monolog/monolog": "^2.0|^3.0",
         "vlucas/phpdotenv": "^5.0|^6.0"
     },
     "require-dev": {
diff --git a/src/JiraClient.php b/src/JiraClient.php
index 6c9c558..02a7dd5 100644
--- a/src/JiraClient.php
+++ b/src/JiraClient.php
@@ -73,6 +73,13 @@ public function __construct(?ConfigurationInterface $configuration = null, ?Logg
 
         $this->json_mapper = new \JsonMapper();
 
+        // Adjust settings for JsonMapper v5.0 BC
+        if (property_exists($this->json_mapper, 'bStrictNullTypesInArrays')) {
+            $this->json_mapper->bStrictNullTypesInArrays = false; // if you want to allow nulls in arrays
+        }
+        $this->json_mapper->bStrictNullTypes = false; // if you want to allow nulls
+        $this->json_mapper->bStrictObjectTypeChecking = false; // if you want to disable strict type checking
+
         // Fix "\JiraRestApi\JsonMapperHelper::class" syntax error, unexpected 'class' (T_CLASS), expecting identifier (T_STRING) or variable (T_VARIABLE) or '{' or '$'
         $this->json_mapper->undefinedPropertyHandler = [new \JiraRestApi\JsonMapperHelper(), 'setUndefinedProperty'];
 
@@ -198,31 +205,7 @@ public function exec(string $context, array|string|null $post_data = null, ?stri
             $this->log->info("Curl $custom_request: $url JsonData=".json_encode($post_data, JSON_UNESCAPED_UNICODE));
         }
 
-        curl_reset($this->curl);
-        $ch = $this->curl;
-        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $this->configuration->getTimeout());
-        curl_setopt($ch, CURLOPT_TIMEOUT, $this->configuration->getTimeout());
-        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
-        curl_setopt($ch, CURLOPT_URL, $url);
-
-        // post_data
-        if (!is_null($post_data)) {
-            // PUT REQUEST
-            if (!is_null($custom_request) && $custom_request == 'PUT') {
-                curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
-                curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
-            }
-            if (!is_null($custom_request) && $custom_request == 'DELETE') {
-                curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'DELETE');
-            } else {
-                curl_setopt($ch, CURLOPT_POST, true);
-                curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
-            }
-        } else {
-            if (!is_null($custom_request) && $custom_request == 'DELETE') {
-                curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'DELETE');
-            }
-        }
+        $ch = $this->prepareCurlRequest($url, $post_data, $custom_request);
 
         // save HTTP Headers
         $curl_http_headers = [
@@ -621,6 +604,37 @@ private function proxyConfigCurlHandle(\CurlHandle $ch): void
         }
     }
 
+    private function prepareCurlRequest(string $url, array|string|null $post_data = null, ?string $custom_request = null)
+    {
+        curl_reset($this->curl);
+        $ch = $this->curl;
+        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $this->configuration->getTimeout());
+        curl_setopt($ch, CURLOPT_TIMEOUT, $this->configuration->getTimeout());
+        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
+        curl_setopt($ch, CURLOPT_URL, $url);
+
+        // post_data
+        if (!is_null($post_data)) {
+            // PUT REQUEST
+            if (!is_null($custom_request) && $custom_request == 'PUT') {
+                curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
+                curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
+            }
+            if (!is_null($custom_request) && $custom_request == 'DELETE') {
+                curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'DELETE');
+            } else {
+                curl_setopt($ch, CURLOPT_POST, true);
+                curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data);
+            }
+        } else {
+            if (!is_null($custom_request) && $custom_request == 'DELETE') {
+                curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'DELETE');
+            }
+        }
+
+        return $ch;
+    }
+
     /**
      * setting REST API url to V2.
      *
diff --git a/src/ServiceDesk/Request/Request.php b/src/ServiceDesk/Request/Request.php
index 3476520..bc86923 100644
--- a/src/ServiceDesk/Request/Request.php
+++ b/src/ServiceDesk/Request/Request.php
@@ -125,6 +125,13 @@ private function map(object $data, object $target)
     {
         $mapper = new JsonMapper();
 
+        // Adjust settings for JsonMapper v5.0 BC
+        if (property_exists($mapper, 'bStrictNullTypesInArrays')) {
+            $mapper->bStrictNullTypesInArrays = false; // if you want to allow nulls in arrays
+        }
+        $mapper->bStrictNullTypes = false; // if you want to allow nulls
+        $mapper->bStrictObjectTypeChecking = false; // if you want to disable strict type checking
+
         return $mapper->map(
             $data,
             $target