diff --git a/README.md b/README.md
index 60db15fd5b..59a2552fdb 100644
--- a/README.md
+++ b/README.md
@@ -305,7 +305,7 @@ By default, Swashbuckle will generate and expose Swagger JSON in version 3.0 of
 ```csharp
 app.UseSwagger(c =>
 {
-    c.SerializeAsV2 = true;
+    c.OpenApiVersion = Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0;
 });
 ```
 
diff --git a/src/Swashbuckle.AspNetCore.Cli/Program.cs b/src/Swashbuckle.AspNetCore.Cli/Program.cs
index 377acb5240..fe516fbc7d 100644
--- a/src/Swashbuckle.AspNetCore.Cli/Program.cs
+++ b/src/Swashbuckle.AspNetCore.Cli/Program.cs
@@ -8,6 +8,7 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Options;
+using Microsoft.OpenApi;
 using Microsoft.OpenApi.Writers;
 using Swashbuckle.AspNetCore.Swagger;
 
@@ -15,6 +16,9 @@ namespace Swashbuckle.AspNetCore.Cli
 {
     internal class Program
     {
+        private const string OpenApiVersionOption = "--openapiversion";
+        private const string SerializeAsV2Flag = "--serializeasv2";
+
         public static int Main(string[] args)
         {
             // Helper to simplify command line parsing etc.
@@ -26,7 +30,7 @@ public static int Main(string[] args)
             // startupassembly and it's transitive dependencies. See https://github.com/dotnet/coreclr/issues/13277 for more.
 
             // > dotnet swagger tofile ...
-            runner.SubCommand("tofile", "retrieves Swagger from a startup assembly, and writes to file ", c =>
+            runner.SubCommand("tofile", "retrieves Swagger from a startup assembly, and writes to file", c =>
             {
                 c.Argument("startupassembly", "relative path to the application's startup assembly");
                 c.Argument("swaggerdoc", "name of the swagger doc you want to retrieve, as configured in your startup class");
@@ -34,17 +38,20 @@ public static int Main(string[] args)
                 c.Option("--output", "relative path where the Swagger will be output, defaults to stdout");
                 c.Option("--host", "a specific host to include in the Swagger output");
                 c.Option("--basepath", "a specific basePath to include in the Swagger output");
-                c.Option("--serializeasv2", "output Swagger in the V2 format rather than V3", true);
+                c.Option(OpenApiVersionOption, "output Swagger in the specified version, defaults to 3.0");
                 c.Option("--yaml", "exports swagger in a yaml format", true);
 
+                // TODO Remove this option in the major version that adds support for OpenAPI 3.1
+                c.Option(SerializeAsV2Flag, "output Swagger in the V2 format rather than V3 [deprecated]", true);
+
                 c.OnRun((namedArgs) =>
                 {
                     string subProcessCommandLine = PrepareCommandLine(args, namedArgs);
 
-                    var subProcess = Process.Start("dotnet", subProcessCommandLine);
+                    using var child = Process.Start("dotnet", subProcessCommandLine);
 
-                    subProcess.WaitForExit();
-                    return subProcess.ExitCode;
+                    child.WaitForExit();
+                    return child.ExitCode;
                 });
             });
 
@@ -56,8 +63,12 @@ public static int Main(string[] args)
                 c.Option("--output", "");
                 c.Option("--host", "");
                 c.Option("--basepath", "");
-                c.Option("--serializeasv2", "", true);
+                c.Option(OpenApiVersionOption, "");
                 c.Option("--yaml", "", true);
+
+                // TODO Remove this option in the major version that adds support for OpenAPI 3.1
+                c.Option(SerializeAsV2Flag, "", true);
+
                 c.OnRun((namedArgs) =>
                 {
                     SetupAndRetrieveSwaggerProviderAndOptions(namedArgs, out var swaggerProvider, out var swaggerOptions);
@@ -94,24 +105,40 @@ public static int Main(string[] args)
                         writer = new OpenApiJsonWriter(streamWriter);
                     }
 
-                    if (namedArgs.ContainsKey("--serializeasv2"))
+                    OpenApiSpecVersion specVersion = OpenApiSpecVersion.OpenApi3_0;
+
+                    if (namedArgs.TryGetValue(OpenApiVersionOption, out var versionArg))
                     {
-                        if (swaggerDocumentSerializer != null)
+                        specVersion = versionArg switch
                         {
-                            swaggerDocumentSerializer.SerializeDocument(swagger, writer, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0);
-                        }
-                        else
-                        {
-                            swagger.SerializeAsV2(writer);
-                        }
+                            "2.0" => OpenApiSpecVersion.OpenApi2_0,
+                            "3.0" => OpenApiSpecVersion.OpenApi3_0,
+                            _ => throw new NotSupportedException($"The specified OpenAPI version \"{versionArg}\" is not supported."),
+                        };
                     }
-                    else if (swaggerDocumentSerializer != null)
+                    else if (namedArgs.ContainsKey(SerializeAsV2Flag))
+                    {
+                        specVersion = OpenApiSpecVersion.OpenApi2_0;
+                        WriteSerializeAsV2DeprecationWarning();
+                    }
+
+                    if (swaggerDocumentSerializer != null)
                     {
-                        swaggerDocumentSerializer.SerializeDocument(swagger, writer, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi3_0);
+                        swaggerDocumentSerializer.SerializeDocument(swagger, writer, specVersion);
                     }
                     else
                     {
-                        swagger.SerializeAsV3(writer);
+                        switch (specVersion)
+                        {
+                            case OpenApiSpecVersion.OpenApi2_0:
+                                swagger.SerializeAsV2(writer);
+                                break;
+
+                            case OpenApiSpecVersion.OpenApi3_0:
+                            default:
+                                swagger.SerializeAsV3(writer);
+                                break;
+                        }
                     }
 
                     if (outputPath != null)
@@ -132,10 +159,10 @@ public static int Main(string[] args)
                 {
                     string subProcessCommandLine = PrepareCommandLine(args, namedArgs);
 
-                    var subProcess = Process.Start("dotnet", subProcessCommandLine);
+                    using var child = Process.Start("dotnet", subProcessCommandLine);
 
-                    subProcess.WaitForExit();
-                    return subProcess.ExitCode;
+                    child.WaitForExit();
+                    return child.ExitCode;
                 });
             });
 
@@ -147,7 +174,7 @@ public static int Main(string[] args)
                 c.OnRun((namedArgs) =>
                 {
                     SetupAndRetrieveSwaggerProviderAndOptions(namedArgs, out var swaggerProvider, out var swaggerOptions);
-                    IList<string> docNames = new List<string>();
+                    IList<string> docNames = [];
 
                     string outputPath = namedArgs.TryGetValue("--output", out var arg1)
                         ? Path.Combine(Directory.GetCurrentDirectory(), arg1)
@@ -185,7 +212,7 @@ public static int Main(string[] args)
             return runner.Run(args);
         }
 
-        private static void SetupAndRetrieveSwaggerProviderAndOptions(System.Collections.Generic.IDictionary<string, string> namedArgs, out ISwaggerProvider swaggerProvider, out IOptions<SwaggerOptions> swaggerOptions)
+        private static void SetupAndRetrieveSwaggerProviderAndOptions(IDictionary<string, string> namedArgs, out ISwaggerProvider swaggerProvider, out IOptions<SwaggerOptions> swaggerOptions)
         {
             // 1) Configure host with provided startupassembly
             var startupAssembly = AssemblyLoadContext.Default.LoadFromAssemblyPath(
@@ -199,7 +226,7 @@ private static void SetupAndRetrieveSwaggerProviderAndOptions(System.Collections
             swaggerOptions = serviceProvider.GetService<IOptions<SwaggerOptions>>();
         }
 
-        private static string PrepareCommandLine(string[] args, System.Collections.Generic.IDictionary<string, string> namedArgs)
+        private static string PrepareCommandLine(string[] args, IDictionary<string, string> namedArgs)
         {
             if (!File.Exists(namedArgs["startupassembly"]))
             {
@@ -222,7 +249,7 @@ private static string PrepareCommandLine(string[] args, System.Collections.Gener
                 EscapePath(runtimeConfig),
                 EscapePath(typeof(Program).GetTypeInfo().Assembly.Location),
                 commandName,
-                string.Join(" ", subProcessArguments.Select(x => EscapePath(x)))
+                string.Join(" ", subProcessArguments.Select(EscapePath))
             );
             return subProcessCommandLine;
         }
@@ -301,5 +328,21 @@ private static bool TryGetCustomHost<THost>(
             host = (THost)factoryMethod.Invoke(null, null);
             return true;
         }
+
+        private static void WriteSerializeAsV2DeprecationWarning()
+        {
+            const string AppName = "Swashbuckle.AspNetCore.Cli";
+
+            string message = $"The {SerializeAsV2Flag} flag will be removed in a future version of {AppName}. Use the {OpenApiVersionOption} option instead.";
+
+            Console.WriteLine(message);
+
+            // See https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions#setting-a-warning-message
+            // and https://docs.github.com/actions/writing-workflows/choosing-what-your-workflow-does/store-information-in-variables#default-environment-variables
+            if (Environment.GetEnvironmentVariable("GITHUB_ACTIONS") is "true")
+            {
+                Console.WriteLine($"::warning title={AppName}::{message}");
+            }
+        }
     }
 }
diff --git a/src/Swashbuckle.AspNetCore.Swagger/DependencyInjection/SwaggerBuilderExtensions.cs b/src/Swashbuckle.AspNetCore.Swagger/DependencyInjection/SwaggerBuilderExtensions.cs
index f381631052..db9c813e47 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/DependencyInjection/SwaggerBuilderExtensions.cs
+++ b/src/Swashbuckle.AspNetCore.Swagger/DependencyInjection/SwaggerBuilderExtensions.cs
@@ -53,22 +53,22 @@ public static IEndpointConventionBuilder MapSwagger(
                 throw new ArgumentException("Pattern must contain '{documentName}' parameter", nameof(pattern));
             }
 
-            Action<SwaggerOptions> endpointSetupAction = options =>
+            var pipeline = endpoints.CreateApplicationBuilder()
+                .UseSwagger(Configure)
+                .Build();
+
+            return endpoints.MapGet(pattern, pipeline);
+
+            void Configure(SwaggerOptions options)
             {
                 var endpointOptions = new SwaggerEndpointOptions();
 
                 setupAction?.Invoke(endpointOptions);
 
                 options.RouteTemplate = pattern;
-                options.SerializeAsV2 = endpointOptions.SerializeAsV2;
+                options.OpenApiVersion = endpointOptions.OpenApiVersion;
                 options.PreSerializeFilters.AddRange(endpointOptions.PreSerializeFilters);
-            };
-
-            var pipeline = endpoints.CreateApplicationBuilder()
-                .UseSwagger(endpointSetupAction)
-                .Build();
-
-            return endpoints.MapGet(pattern, pipeline);
+            }
         }
 #endif
     }
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Shipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Shipped.txt
index 0b8e3fa25f..60897ad016 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Shipped.txt
+++ b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Shipped.txt
@@ -15,8 +15,6 @@ Swashbuckle.AspNetCore.Swagger.ISwaggerDocumentMetadataProvider
 Swashbuckle.AspNetCore.Swagger.ISwaggerDocumentMetadataProvider.GetDocumentNames() -> System.Collections.Generic.IList<string>
 Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions
 Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.PreSerializeFilters.get -> System.Collections.Generic.List<System.Action<Microsoft.OpenApi.Models.OpenApiDocument, Microsoft.AspNetCore.Http.HttpRequest>>
-Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
-Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SwaggerEndpointOptions() -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.CustomDocumentSerializer.get -> Swashbuckle.AspNetCore.Swagger.ISwaggerDocumentSerializer
@@ -24,8 +22,6 @@ Swashbuckle.AspNetCore.Swagger.SwaggerOptions.CustomDocumentSerializer.set -> vo
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.PreSerializeFilters.get -> System.Collections.Generic.List<System.Action<Microsoft.OpenApi.Models.OpenApiDocument, Microsoft.AspNetCore.Http.HttpRequest>>
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.RouteTemplate.get -> string
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.RouteTemplate.set -> void
-Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
-Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void
 Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SwaggerOptions() -> void
 Swashbuckle.AspNetCore.Swagger.UnknownSwaggerDocument
 Swashbuckle.AspNetCore.Swagger.UnknownSwaggerDocument.UnknownSwaggerDocument(string documentName, System.Collections.Generic.IEnumerable<string> knownDocuments) -> void
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Unshipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Unshipped.txt
index e69de29bb2..7d95464edb 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Unshipped.txt
+++ b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/PublicAPI.Unshipped.txt
@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.OpenApiVersion.get -> Microsoft.OpenApi.OpenApiSpecVersion
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.OpenApiVersion.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.OpenApiVersion.get -> Microsoft.OpenApi.OpenApiSpecVersion
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.OpenApiVersion.set -> void
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net6.0/PublicAPI.Shipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net6.0/PublicAPI.Shipped.txt
new file mode 100644
index 0000000000..262c06994a
--- /dev/null
+++ b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net6.0/PublicAPI.Shipped.txt
@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net6.0/PublicAPI.Unshipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net6.0/PublicAPI.Unshipped.txt
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net8.0/PublicAPI.Shipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net8.0/PublicAPI.Shipped.txt
new file mode 100644
index 0000000000..262c06994a
--- /dev/null
+++ b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net8.0/PublicAPI.Shipped.txt
@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net8.0/PublicAPI.Unshipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net8.0/PublicAPI.Unshipped.txt
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net9.0/PublicAPI.Shipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net9.0/PublicAPI.Shipped.txt
new file mode 100644
index 0000000000..262c06994a
--- /dev/null
+++ b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net9.0/PublicAPI.Shipped.txt
@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net9.0/PublicAPI.Unshipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/net9.0/PublicAPI.Unshipped.txt
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/netstandard2.0/PublicAPI.Shipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/netstandard2.0/PublicAPI.Shipped.txt
new file mode 100644
index 0000000000..262c06994a
--- /dev/null
+++ b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/netstandard2.0/PublicAPI.Shipped.txt
@@ -0,0 +1,4 @@
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerEndpointOptions.SerializeAsV2.set -> void
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.get -> bool
+Swashbuckle.AspNetCore.Swagger.SwaggerOptions.SerializeAsV2.set -> void
diff --git a/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt b/src/Swashbuckle.AspNetCore.Swagger/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/src/Swashbuckle.AspNetCore.Swagger/SwaggerEndpointOptions.cs b/src/Swashbuckle.AspNetCore.Swagger/SwaggerEndpointOptions.cs
index a6d60c483c..258a4214aa 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/SwaggerEndpointOptions.cs
+++ b/src/Swashbuckle.AspNetCore.Swagger/SwaggerEndpointOptions.cs
@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
+using Microsoft.OpenApi;
 using Microsoft.OpenApi.Models;
 
 namespace Swashbuckle.AspNetCore.Swagger
@@ -7,15 +8,27 @@ public class SwaggerEndpointOptions
     {
         public SwaggerEndpointOptions()
         {
-            PreSerializeFilters = new List<Action<OpenApiDocument, HttpRequest>>();
-            SerializeAsV2 = false;
+            PreSerializeFilters = [];
+            OpenApiVersion = OpenApiSpecVersion.OpenApi3_0;
         }
 
+        /// <summary>
+        /// Return Swagger JSON/YAML in the V2.0 format rather than V3.0.
+        /// </summary>
+        [Obsolete($"This property will be removed in a future version of Swashbuckle.AspNetCore. Use the {nameof(OpenApiVersion)} property instead.")]
+        public bool SerializeAsV2
+        {
+            get => OpenApiVersion == OpenApiSpecVersion.OpenApi2_0;
+            set => OpenApiVersion = value ? OpenApiSpecVersion.OpenApi2_0 : OpenApiSpecVersion.OpenApi3_0;
+        }
 
         /// <summary>
-        /// Return Swagger JSON in the V2 format rather than V3
+        /// Gets or sets the OpenAPI (Swagger) document version to use.
         /// </summary>
-        public bool SerializeAsV2 { get; set; }
+        /// <remarks>
+        /// The default value is <see cref="OpenApiSpecVersion.OpenApi3_0"/>.
+        /// </remarks>
+        public OpenApiSpecVersion OpenApiVersion { get; set; }
 
         /// <summary>
         /// Actions that can be applied SwaggerDocument's before they're serialized to JSON.
diff --git a/src/Swashbuckle.AspNetCore.Swagger/SwaggerMiddleware.cs b/src/Swashbuckle.AspNetCore.Swagger/SwaggerMiddleware.cs
index 80a48f9958..1e63306458 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/SwaggerMiddleware.cs
+++ b/src/Swashbuckle.AspNetCore.Swagger/SwaggerMiddleware.cs
@@ -14,6 +14,8 @@ namespace Swashbuckle.AspNetCore.Swagger
 {
     internal sealed class SwaggerMiddleware
     {
+        private static readonly Encoding UTF8WithoutBom = new UTF8Encoding(false);
+
         private readonly RequestDelegate _next;
         private readonly SwaggerOptions _options;
         private readonly TemplateMatcher _requestMatcher;
@@ -90,7 +92,7 @@ public async Task Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvid
             }
             catch (UnknownSwaggerDocument)
             {
-                RespondWithNotFound(httpContext.Response);
+                httpContext.Response.StatusCode = 404;
             }
         }
 
@@ -131,60 +133,66 @@ private bool RequestingSwaggerDocument(HttpRequest request, out string documentN
             return false;
         }
 
-        private static void RespondWithNotFound(HttpResponse response)
-        {
-            response.StatusCode = 404;
-        }
-
         private async Task RespondWithSwaggerJson(HttpResponse response, OpenApiDocument swagger)
         {
-            response.StatusCode = 200;
-            response.ContentType = "application/json;charset=utf-8";
+            string json;
 
-            using var textWriter = new StringWriter(CultureInfo.InvariantCulture);
-            var jsonWriter = new OpenApiJsonWriter(textWriter);
-
-            if (_options.SerializeAsV2)
-            {
-                if (_options.CustomDocumentSerializer != null)
-                    _options.CustomDocumentSerializer.SerializeDocument(swagger, jsonWriter, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0);
-                else
-                    swagger.SerializeAsV2(jsonWriter);
-            }
-            else
+            using (var textWriter = new StringWriter(CultureInfo.InvariantCulture))
             {
-                if (_options.CustomDocumentSerializer != null)
-                    _options.CustomDocumentSerializer.SerializeDocument(swagger, jsonWriter, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi3_0);
-                else
-                    swagger.SerializeAsV3(jsonWriter);
+                var openApiWriter = new OpenApiJsonWriter(textWriter);
+
+                SerializeDocument(swagger, openApiWriter);
+
+                json = textWriter.ToString();
             }
 
-            await response.WriteAsync(textWriter.ToString(), new UTF8Encoding(false));
+            response.StatusCode = 200;
+            response.ContentType = "application/json;charset=utf-8";
+
+            await response.WriteAsync(json, UTF8WithoutBom);
         }
 
         private async Task RespondWithSwaggerYaml(HttpResponse response, OpenApiDocument swagger)
         {
+            string yaml;
+
+            using (var textWriter = new StringWriter(CultureInfo.InvariantCulture))
+            {
+                var openApiWriter = new OpenApiYamlWriter(textWriter);
+
+                SerializeDocument(swagger, openApiWriter);
+
+                yaml = textWriter.ToString();
+            }
+
             response.StatusCode = 200;
             response.ContentType = "text/yaml;charset=utf-8";
 
-            using var textWriter = new StringWriter(CultureInfo.InvariantCulture);
-            var yamlWriter = new OpenApiYamlWriter(textWriter);
-            if (_options.SerializeAsV2)
+            await response.WriteAsync(yaml, UTF8WithoutBom);
+        }
+
+        private void SerializeDocument(
+            OpenApiDocument document,
+            IOpenApiWriter writer)
+        {
+            if (_options.CustomDocumentSerializer != null)
             {
-                if (_options.CustomDocumentSerializer != null)
-                    _options.CustomDocumentSerializer.SerializeDocument(swagger, yamlWriter, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0);
-                else
-                    swagger.SerializeAsV2(yamlWriter);
+                _options.CustomDocumentSerializer.SerializeDocument(document, writer, _options.OpenApiVersion);
             }
             else
             {
-                if (_options.CustomDocumentSerializer != null)
-                    _options.CustomDocumentSerializer.SerializeDocument(swagger, yamlWriter, Microsoft.OpenApi.OpenApiSpecVersion.OpenApi3_0);
-                else
-                    swagger.SerializeAsV3(yamlWriter);
+                switch (_options.OpenApiVersion)
+                {
+                    case Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0:
+                        document.SerializeAsV2(writer);
+                        break;
+
+                    case Microsoft.OpenApi.OpenApiSpecVersion.OpenApi3_0:
+                    default:
+                        document.SerializeAsV3(writer);
+                        break;
+                }
             }
-
-            await response.WriteAsync(textWriter.ToString(), new UTF8Encoding(false));
         }
     }
 }
diff --git a/src/Swashbuckle.AspNetCore.Swagger/SwaggerOptions.cs b/src/Swashbuckle.AspNetCore.Swagger/SwaggerOptions.cs
index 212fc7a123..0e0fc264fd 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/SwaggerOptions.cs
+++ b/src/Swashbuckle.AspNetCore.Swagger/SwaggerOptions.cs
@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http;
+using Microsoft.OpenApi;
 using Microsoft.OpenApi.Models;
 
 namespace Swashbuckle.AspNetCore.Swagger
@@ -9,8 +10,8 @@ public class SwaggerOptions
 
         public SwaggerOptions()
         {
-            PreSerializeFilters = new List<Action<OpenApiDocument, HttpRequest>>();
-            SerializeAsV2 = false;
+            PreSerializeFilters = [];
+            OpenApiVersion = OpenApiSpecVersion.OpenApi3_0;
         }
 
         /// <summary>
@@ -19,9 +20,22 @@ public SwaggerOptions()
         public string RouteTemplate { get; set; } = DefaultRouteTemplate;
 
         /// <summary>
-        /// Return Swagger JSON/YAML in the V2 format rather than V3
+        /// Return Swagger JSON/YAML in the V2.0 format rather than V3.0.
         /// </summary>
-        public bool SerializeAsV2 { get; set; }
+        [Obsolete($"This property will be removed in a future version of Swashbuckle.AspNetCore. Use the {nameof(OpenApiVersion)} property instead.")]
+        public bool SerializeAsV2
+        {
+            get => OpenApiVersion == OpenApiSpecVersion.OpenApi2_0;
+            set => OpenApiVersion = value ? OpenApiSpecVersion.OpenApi2_0 : OpenApiSpecVersion.OpenApi3_0;
+        }
+
+        /// <summary>
+        /// Gets or sets the OpenAPI (Swagger) document version to use.
+        /// </summary>
+        /// <remarks>
+        /// The default value is <see cref="OpenApiSpecVersion.OpenApi3_0"/>.
+        /// </remarks>
+        public OpenApiSpecVersion OpenApiVersion { get; set; }
 
         /// <summary>
         /// Gets or sets an optional custom <see cref="ISwaggerDocumentSerializer"/> implementation to use to serialize Swagger documents.
diff --git a/src/Swashbuckle.AspNetCore.Swagger/Swashbuckle.AspNetCore.Swagger.csproj b/src/Swashbuckle.AspNetCore.Swagger/Swashbuckle.AspNetCore.Swagger.csproj
index 4108282405..4a69b96afd 100644
--- a/src/Swashbuckle.AspNetCore.Swagger/Swashbuckle.AspNetCore.Swagger.csproj
+++ b/src/Swashbuckle.AspNetCore.Swagger/Swashbuckle.AspNetCore.Swagger.csproj
@@ -38,5 +38,9 @@
     <AdditionalFiles Include="PublicAPI\$(_TargetFrameworkIdentifier)\PublicAPI.Shipped.txt" />
     <AdditionalFiles Include="PublicAPI\$(_TargetFrameworkIdentifier)\PublicAPI.Unshipped.txt" />
   </ItemGroup>
+  <ItemGroup Condition="Exists('PublicAPI\$(TargetFramework)')">
+    <AdditionalFiles Include="PublicAPI\$(TargetFramework)\PublicAPI.Shipped.txt" />
+    <AdditionalFiles Include="PublicAPI\$(TargetFramework)\PublicAPI.Unshipped.txt" />
+  </ItemGroup>
 
 </Project>
diff --git a/src/Swashbuckle.AspNetCore.SwaggerGen/DependencyInjection/DocumentProvider.cs b/src/Swashbuckle.AspNetCore.SwaggerGen/DependencyInjection/DocumentProvider.cs
index f3a2867361..c0bf9d89ae 100644
--- a/src/Swashbuckle.AspNetCore.SwaggerGen/DependencyInjection/DocumentProvider.cs
+++ b/src/Swashbuckle.AspNetCore.SwaggerGen/DependencyInjection/DocumentProvider.cs
@@ -1,4 +1,4 @@
-using Microsoft.Extensions.Options;
+using Microsoft.Extensions.Options;
 using Microsoft.OpenApi.Writers;
 using Swashbuckle.AspNetCore.Swagger;
 using Swashbuckle.AspNetCore.SwaggerGen;
@@ -42,19 +42,24 @@ public async Task GenerateAsync(string documentName, TextWriter writer)
             // Let UnknownSwaggerDocument or other exception bubble up to caller.
             var swagger = await _swaggerProvider.GetSwaggerAsync(documentName, host: null, basePath: null);
             var jsonWriter = new OpenApiJsonWriter(writer);
-            if (_options.SerializeAsV2)
+
+            if (_options.CustomDocumentSerializer != null)
             {
-                if (_options.CustomDocumentSerializer != null)
-                    _options.CustomDocumentSerializer.SerializeDocument(swagger, jsonWriter, OpenApi.OpenApiSpecVersion.OpenApi2_0);
-                else
-                    swagger.SerializeAsV2(jsonWriter);
+                _options.CustomDocumentSerializer.SerializeDocument(swagger, jsonWriter, _options.OpenApiVersion);
             }
             else
             {
-                if (_options.CustomDocumentSerializer != null)
-                    _options.CustomDocumentSerializer.SerializeDocument(swagger, jsonWriter, OpenApi.OpenApiSpecVersion.OpenApi3_0);
-                else
-                    swagger.SerializeAsV3(jsonWriter);
+                switch (_options.OpenApiVersion)
+                {
+                    case OpenApi.OpenApiSpecVersion.OpenApi2_0:
+                        swagger.SerializeAsV2(jsonWriter);
+                        break;
+
+                    default:
+                    case OpenApi.OpenApiSpecVersion.OpenApi3_0:
+                        swagger.SerializeAsV3(jsonWriter);
+                        break;
+                }
             }
         }
     }
diff --git a/test/Swashbuckle.AspNetCore.Cli.Test/ToolTests.cs b/test/Swashbuckle.AspNetCore.Cli.Test/ToolTests.cs
index 127cdc598e..f26c4920b8 100644
--- a/test/Swashbuckle.AspNetCore.Cli.Test/ToolTests.cs
+++ b/test/Swashbuckle.AspNetCore.Cli.Test/ToolTests.cs
@@ -24,12 +24,53 @@ public static void Can_Output_Swagger_Document_Names()
         [Fact]
         public static void Throws_When_Startup_Assembly_Does_Not_Exist()
         {
-            string[] args = ["tofile", "--output", "swagger.json", "--serializeasv2", "./does_not_exist.dll", "v1"];
+            string[] args = ["tofile", "--output", "swagger.json", "--openapiversion", "2.0", "./does_not_exist.dll", "v1"];
             Assert.Throws<FileNotFoundException>(() => Program.Main(args));
         }
 
+        [Theory]
+        [InlineData("a")]
+        [InlineData("1.9")]
+        [InlineData("3.2")]
+        public static void Error_When_OpenApiVersion_Is_Not_Supported(string version)
+        {
+            string[] args =
+            [
+                "tofile",
+                "--output",
+                "swagger.json",
+                "--openapiversion",
+                version,
+                Path.Combine(Directory.GetCurrentDirectory(), "Basic.dll"),
+                "v1"
+            ];
+            Assert.NotEqual(0, Program.Main(args));
+        }
+
         [Fact]
-        public static void Can_Generate_Swagger_Json()
+        public static void Can_Generate_Swagger_Json_v2_OpenApiVersion()
+        {
+            using var document = RunToJsonCommand((outputPath) =>
+            [
+                "tofile",
+                "--output",
+                outputPath,
+                "--openapiversion",
+                "2.0",
+                Path.Combine(Directory.GetCurrentDirectory(), "Basic.dll"),
+                "v1"
+            ]);
+
+            Assert.Equal("2.0", document.RootElement.GetProperty("swagger").GetString());
+
+            // verify one of the endpoints
+            var paths = document.RootElement.GetProperty("paths");
+            var productsPath = paths.GetProperty("/products");
+            Assert.True(productsPath.TryGetProperty("post", out _));
+        }
+
+        [Fact]
+        public static void Can_Generate_Swagger_Json_v2_SerializeAsV2()
         {
             using var document = RunToJsonCommand((outputPath) =>
             [
@@ -41,6 +82,50 @@ public static void Can_Generate_Swagger_Json()
                 "v1"
             ]);
 
+            Assert.Equal("2.0", document.RootElement.GetProperty("swagger").GetString());
+
+            // verify one of the endpoints
+            var paths = document.RootElement.GetProperty("paths");
+            var productsPath = paths.GetProperty("/products");
+            Assert.True(productsPath.TryGetProperty("post", out _));
+        }
+
+        [Fact]
+        public static void Can_Generate_Swagger_Json_v3()
+        {
+            using var document = RunToJsonCommand((outputPath) =>
+            [
+                "tofile",
+                "--output",
+                outputPath,
+                Path.Combine(Directory.GetCurrentDirectory(), "Basic.dll"),
+                "v1"
+            ]);
+
+            Assert.StartsWith("3.0.", document.RootElement.GetProperty("openapi").GetString());
+
+            // verify one of the endpoints
+            var paths = document.RootElement.GetProperty("paths");
+            var productsPath = paths.GetProperty("/products");
+            Assert.True(productsPath.TryGetProperty("post", out _));
+        }
+
+        [Fact]
+        public static void Can_Generate_Swagger_Json_v3_OpenApiVersion()
+        {
+            using var document = RunToJsonCommand((outputPath) =>
+            [
+                "tofile",
+                "--output",
+                outputPath,
+                "--openapiversion",
+                "3.0",
+                Path.Combine(Directory.GetCurrentDirectory(), "Basic.dll"),
+                "v1"
+            ]);
+
+            Assert.StartsWith("3.0.", document.RootElement.GetProperty("openapi").GetString());
+
             // verify one of the endpoints
             var paths = document.RootElement.GetProperty("paths");
             var productsPath = paths.GetProperty("/products");
@@ -59,7 +144,8 @@ public static void Overwrites_Existing_File()
                     "tofile",
                     "--output",
                     outputPath,
-                    "--serializeasv2",
+                    "--openapiversion",
+                    "2.0",
                     Path.Combine(Directory.GetCurrentDirectory(), "Basic.dll"),
                     "v1"
                 ];
@@ -79,7 +165,8 @@ public static void CustomDocumentSerializer_Writes_Custom_V2_Document()
                 "tofile",
                 "--output",
                 outputPath,
-                "--serializeasv2",
+                "--openapiversion",
+                "2.0",
                 Path.Combine(Directory.GetCurrentDirectory(), "CustomDocumentSerializer.dll"),
                 "v1"
             ]);
@@ -115,7 +202,8 @@ public static void Can_Generate_Swagger_Json_ForTopLevelApp()
                 "tofile",
                 "--output",
                 outputPath,
-                "--serializeasv2",
+                "--openapiversion",
+                "2.0",
                 Path.Combine(Directory.GetCurrentDirectory(), "MinimalApp.dll"),
                 "v1"
             ]);
@@ -152,7 +240,8 @@ public static void Creates_New_Folder_Path()
                 "tofile",
                 "--output",
                 outputPath,
-                "--serializeasv2",
+                "--openapiversion",
+                "2.0",
                 Path.Combine(Directory.GetCurrentDirectory(), "Basic.dll"),
                 "v1"
             ], GenerateRandomString(5));
diff --git a/test/Swashbuckle.AspNetCore.IntegrationTests/CustomDocumentSerializerTests.cs b/test/Swashbuckle.AspNetCore.IntegrationTests/CustomDocumentSerializerTests.cs
index 9cb4f0522d..9dfbbc5c7d 100644
--- a/test/Swashbuckle.AspNetCore.IntegrationTests/CustomDocumentSerializerTests.cs
+++ b/test/Swashbuckle.AspNetCore.IntegrationTests/CustomDocumentSerializerTests.cs
@@ -1,4 +1,4 @@
-using System.Text;
+using System.Text;
 using System.Text.Json;
 using Microsoft.Extensions.ApiDescriptions;
 using Microsoft.Extensions.DependencyInjection;
@@ -71,6 +71,17 @@ public async Task DocumentProvider_Writes_Custom_V3_Document()
 
         [Fact]
         public async Task DocumentProvider_Writes_Custom_V2_Document()
+        {
+            await DocumentProviderWritesCustomV2Document(
+                (options) => options.OpenApiVersion = Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0);
+        }
+
+        [Obsolete]
+        [Fact]
+        public async Task DocumentProvider_Writes_Custom_V2_Document_SerializeAsV2()
+            => await DocumentProviderWritesCustomV2Document((options) => options.SerializeAsV2 = true);
+
+        private static async Task DocumentProviderWritesCustomV2Document(Action<SwaggerOptions> configure)
         {
             var testSite = new TestSite(typeof(CustomDocumentSerializer.Startup));
             var server = testSite.BuildServer();
@@ -78,7 +89,8 @@ public async Task DocumentProvider_Writes_Custom_V2_Document()
 
             var documentProvider = services.GetService<IDocumentProvider>();
             var options = services.GetService<IOptions<SwaggerOptions>>();
-            options.Value.SerializeAsV2 = true;
+
+            configure(options.Value);
 
             using var stream = new MemoryStream();
 
diff --git a/test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerIntegrationTests.cs b/test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerIntegrationTests.cs
index 0428ad1c71..03aa71304f 100644
--- a/test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerIntegrationTests.cs
+++ b/test/Swashbuckle.AspNetCore.IntegrationTests/SwaggerIntegrationTests.cs
@@ -119,11 +119,9 @@ public async Task SwaggerMiddleware_CanBeConfiguredMultipleTimes(
         [Theory]
         [InlineData(typeof(MinimalApp.Program), "/swagger/v1/swagger.json")]
         [InlineData(typeof(TopLevelSwaggerDoc.Program), "/swagger/v1.json")]
-#if NET8_0_OR_GREATER
         [InlineData(typeof(MvcWithNullable.Program), "/swagger/v1/swagger.json")]
         [InlineData(typeof(WebApi.Program), "/swagger/v1/swagger.json")]
         [InlineData(typeof(WebApi.Aot.Program), "/swagger/v1/swagger.json")]
-#endif
         public async Task SwaggerEndpoint_ReturnsValidSwaggerJson_Without_Startup(
             Type entryPointType,
             string swaggerRequestUri)
@@ -131,7 +129,6 @@ public async Task SwaggerEndpoint_ReturnsValidSwaggerJson_Without_Startup(
             await SwaggerEndpointReturnsValidSwaggerJson(entryPointType, swaggerRequestUri);
         }
 
-#if NET8_0_OR_GREATER
         [Fact]
         public async Task TypesAreRenderedCorrectly()
         {
@@ -169,7 +166,6 @@ public async Task TypesAreRenderedCorrectly()
                 () => Assert.True(properties.GetProperty("temperatureF").GetProperty("readOnly").GetBoolean()),
             ]);
         }
-#endif
 
         private static async Task SwaggerEndpointReturnsValidSwaggerJson(Type entryPointType, string swaggerRequestUri)
         {
diff --git a/test/WebSites/Basic/Startup.cs b/test/WebSites/Basic/Startup.cs
index da29c4b90d..54c8abc7c7 100644
--- a/test/WebSites/Basic/Startup.cs
+++ b/test/WebSites/Basic/Startup.cs
@@ -8,14 +8,6 @@ namespace Basic
 {
     public class Startup
     {
-        public Startup(IConfiguration configuration)
-        {
-            Configuration = configuration;
-        }
-
-        public IConfiguration Configuration { get; }
-
-        // This method gets called by the runtime. Use this method to add services to the container.
         public void ConfigureServices(IServiceCollection services)
         {
             services.AddControllers();
@@ -66,11 +58,11 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
             {
                 endpoints.MapControllers();
 
-                // Expose Swagger/OpenAPI JSON in new (v3) and old (v2) formats
+                // Expose Swagger/OpenAPI JSON in different formats
                 endpoints.MapSwagger("swagger/{documentName}/swagger.json");
                 endpoints.MapSwagger("swagger/{documentName}/swaggerv2.json", c =>
                 {
-                    c.SerializeAsV2 = true;
+                    c.OpenApiVersion = Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0;
                 });
             });
 
diff --git a/test/WebSites/CustomDocumentSerializer/Startup.cs b/test/WebSites/CustomDocumentSerializer/Startup.cs
index 5ff5964356..196d301c24 100644
--- a/test/WebSites/CustomDocumentSerializer/Startup.cs
+++ b/test/WebSites/CustomDocumentSerializer/Startup.cs
@@ -2,13 +2,6 @@ namespace CustomDocumentSerializer;
 
 public class Startup
 {
-    public Startup(IConfiguration configuration)
-    {
-        Configuration = configuration;
-    }
-
-    public IConfiguration Configuration { get; }
-
     public void ConfigureServices(IServiceCollection services)
     {
         services.AddControllers();
@@ -33,7 +26,7 @@ public void Configure(IApplicationBuilder app)
         {
             endpoints.MapControllers();
             endpoints.MapSwagger("swagger/{documentName}/swagger.json");
-            endpoints.MapSwagger("swagger/{documentName}/swaggerv2.json", c => c.SerializeAsV2 = true);
+            endpoints.MapSwagger("swagger/{documentName}/swaggerv2.json", c => c.OpenApiVersion = Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0);
         });
     }
 }
diff --git a/test/WebSites/ReDoc/Startup.cs b/test/WebSites/ReDoc/Startup.cs
index 06e321c72b..4c392502c4 100644
--- a/test/WebSites/ReDoc/Startup.cs
+++ b/test/WebSites/ReDoc/Startup.cs
@@ -40,7 +40,7 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 
             app.UseSwagger(c =>
             {
-                c.SerializeAsV2 = true;
+                c.OpenApiVersion = Microsoft.OpenApi.OpenApiSpecVersion.OpenApi2_0;
             });
 
             app.UseReDoc(c =>