diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
index 2a3c2ffef01d..db559d3c6685 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
@@ -417,10 +417,16 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
                 op.vendorExtensions.put("x-comment-type", "void");
             }
             // Create a variable to add typing for return value of interface
-            if (op.returnType != null) {
+            if (op.returnType == null) {
+                op.vendorExtensions.put("x-return-type", "void");
+            } else if (op.isArray || op.isMap || isApplicationJsonOrApplicationXml(op)
+                    || !op.returnTypeIsPrimitive // it could make sense to remove it, but it would break retro-compatibility
+            ) {
                 op.vendorExtensions.put("x-return-type", "array|object|null");
+            } else if ("binary".equals(op.returnProperty.dataFormat)) {
+                op.vendorExtensions.put("x-return-type", "mixed");
             } else {
-                op.vendorExtensions.put("x-return-type", "void");
+                op.vendorExtensions.put("x-return-type", op.returnType);
             }
 
             // Add operation's authentication methods to whole interface
@@ -438,6 +444,18 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
         return objs;
     }
 
+    private boolean isApplicationJsonOrApplicationXml(CodegenOperation op) {
+       if (op.produces != null) {
+           for(Map<String, String> produce : op.produces) {
+               String mediaType = produce.get("mediaType");
+               if (isJsonMimeType(mediaType) || isXmlMimeType(mediaType)) {
+                  return true;
+               }
+           }
+       }
+       return false;
+    }
+
     @Override
     public ModelsMap postProcessModels(ModelsMap objs) {
         objs = super.postProcessModels(objs);
diff --git a/modules/openapi-generator/src/main/resources/php-symfony/Controller.mustache b/modules/openapi-generator/src/main/resources/php-symfony/Controller.mustache
index 023b66c90f7d..1c3288d813bb 100644
--- a/modules/openapi-generator/src/main/resources/php-symfony/Controller.mustache
+++ b/modules/openapi-generator/src/main/resources/php-symfony/Controller.mustache
@@ -204,6 +204,10 @@ class Controller extends AbstractController
             return 'application/xml';
         }
 
+        if (in_array('*/*', $accept)) {
+            return $produced[0];
+        }
+
         // If we reach this point, we don't have a common ground between server and client
         return null;
     }
diff --git a/modules/openapi-generator/src/main/resources/php-symfony/serialization/JmsSerializer.mustache b/modules/openapi-generator/src/main/resources/php-symfony/serialization/JmsSerializer.mustache
index 9dfabc9733a3..6c93e947f425 100644
--- a/modules/openapi-generator/src/main/resources/php-symfony/serialization/JmsSerializer.mustache
+++ b/modules/openapi-generator/src/main/resources/php-symfony/serialization/JmsSerializer.mustache
@@ -29,7 +29,13 @@ class JmsSerializer implements SerializerInterface
      */
     public function serialize($data, string $format): string
     {
-        return SerializerBuilder::create()->build()->serialize($data, $this->convertFormat($format));
+        $convertFormat = $this->convertFormat($format);
+        if ($convertFormat !== null) {
+           return SerializerBuilder::create()->build()->serialize($data, $convertFormat);
+        } else {
+           // don't use var_export if $data is already a string: it may corrupt binary strings
+           return is_string($data) ? $data : var_export($data, true);
+        }
     }
 
     /**
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Controller/Controller.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Controller/Controller.php
index e21a2f138131..7d2600dbb6e7 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Controller/Controller.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Controller/Controller.php
@@ -214,6 +214,10 @@ protected function getOutputFormat(string $accept, array $produced): ?string
             return 'application/xml';
         }
 
+        if (in_array('*/*', $accept)) {
+            return $produced[0];
+        }
+
         // If we reach this point, we don't have a common ground between server and client
         return null;
     }
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Service/JmsSerializer.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Service/JmsSerializer.php
index 5abbc6de3fb9..234056cf41d5 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Service/JmsSerializer.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Service/JmsSerializer.php
@@ -29,7 +29,13 @@ public function __construct()
      */
     public function serialize($data, string $format): string
     {
-        return SerializerBuilder::create()->build()->serialize($data, $this->convertFormat($format));
+        $convertFormat = $this->convertFormat($format);
+        if ($convertFormat !== null) {
+           return SerializerBuilder::create()->build()->serialize($data, $convertFormat);
+        } else {
+           // don't use var_export if $data is already a string: it may corrupt binary strings
+           return is_string($data) ? $data : var_export($data, true);
+        }
     }
 
     /**