diff --git a/src/Microsoft.OpenApi.Hidi/OpenApiService.cs b/src/Microsoft.OpenApi.Hidi/OpenApiService.cs
index fd53086d2..7cde3f2fb 100644
--- a/src/Microsoft.OpenApi.Hidi/OpenApiService.cs
+++ b/src/Microsoft.OpenApi.Hidi/OpenApiService.cs
@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
 using System;
@@ -79,7 +79,7 @@ public static async Task TransformOpenApiDocument(HidiOptions options, ILogger l
 
                 // Default to yaml and OpenApiVersion 3 during csdl to OpenApi conversion
                 var openApiFormat = options.OpenApiFormat ?? (!string.IsNullOrEmpty(options.OpenApi) ? GetOpenApiFormat(options.OpenApi, logger) : OpenApiFormat.Yaml);
-                var openApiVersion = options.Version != null ? TryParseOpenApiSpecVersion(options.Version) : OpenApiSpecVersion.OpenApi3_0;
+                var openApiVersion = options.Version != null ? TryParseOpenApiSpecVersion(options.Version) : OpenApiSpecVersion.OpenApi3_1;
 
                 // If ApiManifest is provided, set the referenced OpenAPI document
                 var apiDependency = await FindApiDependency(options.FilterOptions.FilterByApiManifest, logger, cancellationToken).ConfigureAwait(false);
@@ -768,7 +768,7 @@ internal static async Task PluginManifest(HidiOptions options, ILogger logger, C
             // Write OpenAPI to Output folder
             options.Output = new(Path.Combine(options.OutputFolder, "openapi.json"));
             options.TerseOutput = true;
-            WriteOpenApi(options, OpenApiFormat.Json, OpenApiSpecVersion.OpenApi3_0, document, logger);
+            WriteOpenApi(options, OpenApiFormat.Json, OpenApiSpecVersion.OpenApi3_1, document, logger);
 
             // Create OpenAIPluginManifest from ApiDependency and OpenAPI document
             var manifest = new OpenAIPluginManifest
diff --git a/src/Microsoft.OpenApi.Hidi/OpenApiSpecVersionHelper.cs b/src/Microsoft.OpenApi.Hidi/OpenApiSpecVersionHelper.cs
index 234298481..222f7a8c6 100644
--- a/src/Microsoft.OpenApi.Hidi/OpenApiSpecVersionHelper.cs
+++ b/src/Microsoft.OpenApi.Hidi/OpenApiSpecVersionHelper.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT license.
 
 using System;
-using System.Linq;
 
 namespace Microsoft.OpenApi.Hidi
 {
@@ -14,17 +13,30 @@ public static OpenApiSpecVersion TryParseOpenApiSpecVersion(string value)
             {
                 throw new InvalidOperationException("Please provide a version");
             }
-            var res = value.Split('.', StringSplitOptions.RemoveEmptyEntries).FirstOrDefault();
+            // Split the version string by the dot
+            var versionSegments = value.Split('.', StringSplitOptions.RemoveEmptyEntries);
 
-            if (int.TryParse(res, out var result))
+            if (!int.TryParse(versionSegments[0], out var majorVersion)
+                || !int.TryParse(versionSegments[1], out var minorVersion))
             {
-                if (result is >= 2 and < 3)
-                {
-                    return OpenApiSpecVersion.OpenApi2_0;
-                }
+                throw new InvalidOperationException("Invalid version format. Please provide a valid OpenAPI version (e.g., 2.0, 3.0, 3.1).");
             }
 
-            return OpenApiSpecVersion.OpenApi3_0; // default
+            // Check for specific version matches
+            if (majorVersion == 2)
+            {
+                return OpenApiSpecVersion.OpenApi2_0;
+            }
+            else if (majorVersion == 3 && minorVersion == 0)
+            {
+                return OpenApiSpecVersion.OpenApi3_0;
+            }
+            else if (majorVersion == 3 && minorVersion == 1)
+            {
+                return OpenApiSpecVersion.OpenApi3_1;
+            }
+
+            return OpenApiSpecVersion.OpenApi3_1; // default
         }
     }
 }