diff --git a/CMakeLists.txt b/CMakeLists.txt
index d11e809..4b1206c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.16)
-project(expresso VERSION 0.1.5)
+project(expresso VERSION 0.1.6)
 
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
 
diff --git a/include/expresso/constants/cors.h b/include/expresso/constants/cors.h
new file mode 100644
index 0000000..06b4c9e
--- /dev/null
+++ b/include/expresso/constants/cors.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <set>
+#include <string>
+
+namespace expresso {
+
+namespace constants {
+
+namespace cors {
+
+const std::set<std::string> headers = {"accept",
+                                       "access-control-allow-credentials",
+                                       "access-control-allow-headers",
+                                       "access-control-allow-methods",
+                                       "access-control-allow-origin",
+                                       "access-control-expose-headers",
+                                       "access-control-max-age",
+                                       "authorization",
+                                       "content-type",
+                                       "origin",
+                                       "user-agent",
+                                       "x-requested-with"};
+
+const std::string forbidden = "Forbidden";
+
+} // namespace cors
+
+} // namespace constants
+
+} // namespace expresso
\ No newline at end of file
diff --git a/include/expresso/middleware/cors.h b/include/expresso/middleware/cors.h
index 3e73528..44adbdb 100644
--- a/include/expresso/middleware/cors.h
+++ b/include/expresso/middleware/cors.h
@@ -29,9 +29,6 @@ class Cors : public Middleware {
 
   bool use(expresso::core::Request &req,
            expresso::core::Response &res) override;
-
-  static const std::string FORBIDDEN;
-  static const std::set<std::string> HEADERS;
 };
 
 } // namespace middleware
diff --git a/include/expresso/version.h b/include/expresso/version.h
index 9b265fa..cd3e04b 100644
--- a/include/expresso/version.h
+++ b/include/expresso/version.h
@@ -2,4 +2,4 @@
 
 #define EXPRESSO_VERSION_MAJOR 0
 #define EXPRESSO_VERSION_MINOR 1
-#define EXPRESSO_VERSION_PATCH 5
\ No newline at end of file
+#define EXPRESSO_VERSION_PATCH 6
\ No newline at end of file
diff --git a/src/middleware/cors.cpp b/src/middleware/cors.cpp
index 4a09de0..ff8a97e 100644
--- a/src/middleware/cors.cpp
+++ b/src/middleware/cors.cpp
@@ -1,29 +1,9 @@
+#include <expresso/constants/cors.h>
 #include <expresso/middleware/cors.h>
 
-namespace expresso::middleware {
-
-const std::set<std::string> Cors::HEADERS = {
-    "accept",
-    "access-control-allow-credentials",
-    "access-control-allow-headers",
-    "access-control-allow-methods",
-    "access-control-allow-origin",
-    "access-control-expose-headers",
-    "access-control-max-age",
-    "authorization",
-    "content-type",
-    "origin",
-    "user-agent",
-    "x-requested-with",
-};
-
-const std::string Cors::FORBIDDEN = "Forbidden";
-
-} // namespace expresso::middleware
-
 expresso::middleware::Cors::Cors()
     : credentials(false), allowAllOrigins(false), allowedHeaders("") {
-  for (std::string _header : this->HEADERS) {
+  for (std::string _header : expresso::constants::cors::headers) {
     this->headers.insert(_header);
   }
 
@@ -87,7 +67,7 @@ bool expresso::middleware::Cors::use(expresso::core::Request &req,
   if (requestOrigin == "") {
     res.set("access-control-allow-origin", "null");
     res.status(expresso::enums::STATUS_CODE::FORBIDDEN)
-        .send(expresso::middleware::Cors::FORBIDDEN);
+        .send(expresso::constants::cors::forbidden);
     return false;
   }
 
@@ -103,7 +83,7 @@ bool expresso::middleware::Cors::use(expresso::core::Request &req,
   if (!isOriginPresent) {
     res.set("access-control-allow-origin", "null");
     res.status(expresso::enums::STATUS_CODE::FORBIDDEN)
-        .send(expresso::middleware::Cors::FORBIDDEN);
+        .send(expresso::constants::cors::forbidden);
     return false;
   }