diff --git a/CHANGELOG.md b/CHANGELOG.md
index 97950d6..fcde21d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.26.4] - 2025-11-26
+
+### 🔧 Fixed
+
+- **n8n 1.121 Compatibility**: Added support for new workflow settings introduced in n8n 1.121
+  - Added `availableInMCP` (boolean) to settings whitelist - controls "Available in MCP" toggle
+  - Added `callerPolicy` to settings whitelist - was already in schema but missing from sanitization
+  - Both settings are now preserved during workflow updates instead of being silently stripped
+  - Settings can be toggled via `updateSettings` operation: `{type: "updateSettings", settings: {availableInMCP: true}}`
+
+**Conceived by Romuald Członkowski - [AiAdvisors](https://www.aiadvisors.pl/en)**
+
 ## [2.26.3] - 2025-11-26
 
 ### 🔧 Fixed
diff --git a/data/nodes.db b/data/nodes.db
index bcf1ed8..873ca10 100644
Binary files a/data/nodes.db and b/data/nodes.db differ
diff --git a/package.json b/package.json
index 14e992a..c12e667 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.26.3",
+  "version": "2.26.4",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
diff --git a/package.runtime.json b/package.runtime.json
index 84c02f3..c8714fa 100644
--- a/package.runtime.json
+++ b/package.runtime.json
@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp-runtime",
-  "version": "2.26.3",
+  "version": "2.26.4",
   "description": "n8n MCP Server Runtime Dependencies Only",
   "private": true,
   "dependencies": {
diff --git a/src/services/n8n-validation.ts b/src/services/n8n-validation.ts
index c839fdd..3371fde 100644
--- a/src/services/n8n-validation.ts
+++ b/src/services/n8n-validation.ts
@@ -62,6 +62,7 @@ export const workflowSettingsSchema = z.object({
   executionTimeout: z.number().optional(),
   errorWorkflow: z.string().optional(),
   callerPolicy: z.enum(['any', 'workflowsFromSameOwner', 'workflowsFromAList']).optional(),
+  availableInMCP: z.boolean().optional(),
 });
 
 // Default settings for workflow creation
@@ -181,7 +182,9 @@ export function cleanWorkflowForUpdate(workflow: Workflow): Partial<Workflow> {
     'executionTimeout',
     'errorWorkflow',
     'timezone',
-    'executionOrder'
+    'executionOrder',
+    'callerPolicy',
+    'availableInMCP',
   ];
 
   if (cleanedWorkflow.settings && typeof cleanedWorkflow.settings === 'object') {
diff --git a/tests/unit/services/n8n-validation.test.ts b/tests/unit/services/n8n-validation.test.ts
index 045c26e..0211818 100644
--- a/tests/unit/services/n8n-validation.test.ts
+++ b/tests/unit/services/n8n-validation.test.ts
@@ -403,45 +403,47 @@ describe('n8n-validation', () => {
           settings: {
             executionOrder: 'v1' as const,
             saveDataSuccessExecution: 'none' as const,
-            callerPolicy: 'workflowsFromSameOwner' as const, // Filtered out (not in OpenAPI spec)
+            callerPolicy: 'workflowsFromSameOwner' as const, // Now whitelisted (n8n 1.121+)
             timeSavedPerExecution: 5, // Filtered out (UI-only property)
           },
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
 
-        // Unsafe properties filtered out, safe properties kept
+        // Unsafe properties filtered out, safe properties kept (callerPolicy now whitelisted)
         expect(cleaned.settings).toEqual({
           executionOrder: 'v1',
-          saveDataSuccessExecution: 'none'
+          saveDataSuccessExecution: 'none',
+          callerPolicy: 'workflowsFromSameOwner'
         });
-        expect(cleaned.settings).not.toHaveProperty('callerPolicy');
         expect(cleaned.settings).not.toHaveProperty('timeSavedPerExecution');
       });
 
-      it('should filter out callerPolicy (Issue #248 - API limitation)', () => {
+      it('should preserve callerPolicy and availableInMCP (n8n 1.121+ settings)', () => {
         const workflow = {
           name: 'Test Workflow',
           nodes: [],
           connections: {},
           settings: {
             executionOrder: 'v1' as const,
-            callerPolicy: 'workflowsFromSameOwner' as const, // Filtered out
+            callerPolicy: 'workflowsFromSameOwner' as const, // Now whitelisted
+            availableInMCP: true, // New in n8n 1.121
             errorWorkflow: 'N2O2nZy3aUiBRGFN',
           },
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
 
-        // callerPolicy filtered out (causes API errors), safe properties kept
+        // callerPolicy and availableInMCP now whitelisted (n8n 1.121+)
         expect(cleaned.settings).toEqual({
           executionOrder: 'v1',
+          callerPolicy: 'workflowsFromSameOwner',
+          availableInMCP: true,
           errorWorkflow: 'N2O2nZy3aUiBRGFN'
         });
-        expect(cleaned.settings).not.toHaveProperty('callerPolicy');
       });
 
-      it('should filter all settings properties correctly (Issue #248 - API design)', () => {
+      it('should preserve all whitelisted settings properties including callerPolicy (Issue #248 - updated for n8n 1.121)', () => {
         const workflow = {
           name: 'Test Workflow',
           nodes: [],
@@ -455,14 +457,14 @@ describe('n8n-validation', () => {
             saveExecutionProgress: false,
             executionTimeout: 300,
             errorWorkflow: 'error-workflow-id',
-            callerPolicy: 'workflowsFromAList' as const, // Filtered out (not in OpenAPI spec)
+            callerPolicy: 'workflowsFromAList' as const, // Now whitelisted (n8n 1.121+)
+            availableInMCP: false, // New in n8n 1.121
           },
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
 
-        // Safe properties kept, unsafe properties filtered out
-        // See: https://community.n8n.io/t/api-workflow-update-endpoint-doesnt-support-setting-callerpolicy/161916
+        // All whitelisted properties kept including callerPolicy and availableInMCP
         expect(cleaned.settings).toEqual({
           executionOrder: 'v0',
           timezone: 'UTC',
@@ -471,9 +473,10 @@ describe('n8n-validation', () => {
           saveManualExecutions: false,
           saveExecutionProgress: false,
           executionTimeout: 300,
-          errorWorkflow: 'error-workflow-id'
+          errorWorkflow: 'error-workflow-id',
+          callerPolicy: 'workflowsFromAList',
+          availableInMCP: false
         });
-        expect(cleaned.settings).not.toHaveProperty('callerPolicy');
       });
 
       it('should handle workflows without settings gracefully', () => {
@@ -494,7 +497,6 @@ describe('n8n-validation', () => {
           nodes: [],
           connections: {},
           settings: {
-            callerPolicy: 'workflowsFromSameOwner' as const, // Filtered out
             timeSavedPerExecution: 5, // Filtered out (UI-only)
             someOtherProperty: 'value', // Filtered out
           },
@@ -514,19 +516,19 @@ describe('n8n-validation', () => {
           connections: {},
           settings: {
             executionOrder: 'v1' as const, // Whitelisted
-            callerPolicy: 'workflowsFromSameOwner' as const, // Filtered out
+            callerPolicy: 'workflowsFromSameOwner' as const, // Now whitelisted (n8n 1.121+)
             timezone: 'America/New_York', // Whitelisted
             someOtherProperty: 'value', // Filtered out
           },
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
-        // Should keep only whitelisted properties
+        // Should keep only whitelisted properties (callerPolicy now whitelisted)
         expect(cleaned.settings).toEqual({
           executionOrder: 'v1',
+          callerPolicy: 'workflowsFromSameOwner',
           timezone: 'America/New_York'
         });
-        expect(cleaned.settings).not.toHaveProperty('callerPolicy');
         expect(cleaned.settings).not.toHaveProperty('someOtherProperty');
       });
     });