diff --git a/apps/files_sharing/openapi.json b/apps/files_sharing/openapi.json
index 89c82843939..627c25ce8ea 100644
--- a/apps/files_sharing/openapi.json
+++ b/apps/files_sharing/openapi.json
@@ -1492,7 +1492,7 @@
                         }
                     },
                     {
-                        "name": "X-NC-Preview",
+                        "name": "x-nc-preview",
                         "in": "header",
                         "schema": {
                             "type": "string"
diff --git a/apps/webhook_listeners/openapi.json b/apps/webhook_listeners/openapi.json
index 84610d204bb..340d2d21337 100644
--- a/apps/webhook_listeners/openapi.json
+++ b/apps/webhook_listeners/openapi.json
@@ -256,7 +256,7 @@
                 },
                 "parameters": [
                     {
-                        "name": "EX-APP-ID",
+                        "name": "ex-app-id",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -556,7 +556,7 @@
                         }
                     },
                     {
-                        "name": "EX-APP-ID",
+                        "name": "ex-app-id",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -809,7 +809,7 @@
                     {
                         "name": "appid",
                         "in": "path",
-                        "description": "id of the app, as in the EX-APP-ID for creation",
+                        "description": "id of the app, as in the ex-app-id for creation",
                         "required": true,
                         "schema": {
                             "type": "string"
diff --git a/core/openapi-full.json b/core/openapi-full.json
index 298be2e59d8..5edb86992dc 100644
--- a/core/openapi-full.json
+++ b/core/openapi-full.json
@@ -1173,7 +1173,7 @@
                 ],
                 "parameters": [
                     {
-                        "name": "USER_AGENT",
+                        "name": "user-agent",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -8066,7 +8066,7 @@
                 ],
                 "parameters": [
                     {
-                        "name": "USER_AGENT",
+                        "name": "user-agent",
                         "in": "header",
                         "schema": {
                             "type": "string"
diff --git a/core/openapi.json b/core/openapi.json
index 7462890bb4b..5f9178202eb 100644
--- a/core/openapi.json
+++ b/core/openapi.json
@@ -1173,7 +1173,7 @@
                 ],
                 "parameters": [
                     {
-                        "name": "USER_AGENT",
+                        "name": "user-agent",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -8066,7 +8066,7 @@
                 ],
                 "parameters": [
                     {
-                        "name": "USER_AGENT",
+                        "name": "user-agent",
                         "in": "header",
                         "schema": {
                             "type": "string"
diff --git a/openapi.json b/openapi.json
index b7350b4b1fa..88d8450bd43 100644
--- a/openapi.json
+++ b/openapi.json
@@ -4645,7 +4645,7 @@
                 ],
                 "parameters": [
                     {
-                        "name": "USER_AGENT",
+                        "name": "user-agent",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -11585,7 +11585,7 @@
                 ],
                 "parameters": [
                     {
-                        "name": "USER_AGENT",
+                        "name": "user-agent",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -19842,7 +19842,7 @@
                         }
                     },
                     {
-                        "name": "X-NC-Preview",
+                        "name": "x-nc-preview",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -30808,7 +30808,7 @@
                 },
                 "parameters": [
                     {
-                        "name": "EX-APP-ID",
+                        "name": "ex-app-id",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -31108,7 +31108,7 @@
                         }
                     },
                     {
-                        "name": "EX-APP-ID",
+                        "name": "ex-app-id",
                         "in": "header",
                         "schema": {
                             "type": "string"
@@ -31361,7 +31361,7 @@
                     {
                         "name": "appid",
                         "in": "path",
-                        "description": "id of the app, as in the EX-APP-ID for creation",
+                        "description": "id of the app, as in the ex-app-id for creation",
                         "required": true,
                         "schema": {
                             "type": "string"
diff --git a/tests/Core/Controller/AppPasswordControllerTest.php b/tests/Core/Controller/AppPasswordControllerTest.php
index b33033edac3..eb1566eca8b 100644
--- a/tests/Core/Controller/AppPasswordControllerTest.php
+++ b/tests/Core/Controller/AppPasswordControllerTest.php
@@ -123,7 +123,7 @@ class AppPasswordControllerTest extends TestCase {
 		$credentials->method('getLoginName')
 			->willReturn('myLoginName');
 		$this->request->method('getHeader')
-			->with('USER_AGENT')
+			->with('user-agent')
 			->willReturn('myUA');
 		$this->random->method('generate')
 			->with(
@@ -164,7 +164,7 @@ class AppPasswordControllerTest extends TestCase {
 		$credentials->method('getLoginName')
 			->willReturn('myLoginName');
 		$this->request->method('getHeader')
-			->with('USER_AGENT')
+			->with('user-agent')
 			->willReturn('myUA');
 		$this->random->method('generate')
 			->with(
diff --git a/tests/Core/Controller/ClientFlowLoginControllerTest.php b/tests/Core/Controller/ClientFlowLoginControllerTest.php
index b10055ef542..c9ccf9ac674 100644
--- a/tests/Core/Controller/ClientFlowLoginControllerTest.php
+++ b/tests/Core/Controller/ClientFlowLoginControllerTest.php
@@ -119,7 +119,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 		$this->request
 			->method('getHeader')
 			->willReturnMap([
-				['USER_AGENT', 'Mac OS X Sync Client'],
+				['user-agent', 'Mac OS X Sync Client'],
 				['OCS-APIREQUEST', 'true'],
 			]);
 		$this->random
@@ -178,7 +178,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 		$this->request
 			->method('getHeader')
 			->willReturnMap([
-				['USER_AGENT', 'Mac OS X Sync Client'],
+				['user-agent', 'Mac OS X Sync Client'],
 				['OCS-APIREQUEST', 'false'],
 			]);
 		$client = new Client();
@@ -555,7 +555,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 				[
 					['X-Forwarded-Proto', 'http'],
 					['X-Forwarded-Ssl', 'off'],
-					['USER_AGENT', ''],
+					['user-agent', ''],
 				],
 				'http',
 				'http',
@@ -564,7 +564,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 				[
 					['X-Forwarded-Proto', 'http'],
 					['X-Forwarded-Ssl', 'off'],
-					['USER_AGENT', ''],
+					['user-agent', ''],
 				],
 				'https',
 				'https',
@@ -573,7 +573,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 				[
 					['X-Forwarded-Proto', 'https'],
 					['X-Forwarded-Ssl', 'off'],
-					['USER_AGENT', ''],
+					['user-agent', ''],
 				],
 				'http',
 				'https',
@@ -582,7 +582,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 				[
 					['X-Forwarded-Proto', 'https'],
 					['X-Forwarded-Ssl', 'on'],
-					['USER_AGENT', ''],
+					['user-agent', ''],
 				],
 				'http',
 				'https',
@@ -591,7 +591,7 @@ class ClientFlowLoginControllerTest extends TestCase {
 				[
 					['X-Forwarded-Proto', 'http'],
 					['X-Forwarded-Ssl', 'on'],
-					['USER_AGENT', ''],
+					['user-agent', ''],
 				],
 				'http',
 				'https',
diff --git a/tests/Core/Controller/PreviewControllerTest.php b/tests/Core/Controller/PreviewControllerTest.php
index e7ecba27064..2c2411e666f 100644
--- a/tests/Core/Controller/PreviewControllerTest.php
+++ b/tests/Core/Controller/PreviewControllerTest.php
@@ -265,7 +265,7 @@ class PreviewControllerTest extends \Test\TestCase {
 
 		$this->request
 			->method('getHeader')
-			->with('X-NC-Preview')
+			->with('x-nc-preview')
 			->willReturn('true');
 
 		$preview = $this->createMock(ISimpleFile::class);