diff --git a/Package.swift b/Package.swift
index 9228dd4..50f56cd 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,7 +1,26 @@
 // swift-tools-version: 5.8
-
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift OpenAPI Vapor open source project
+//
+// Copyright (c) 2023 the Swift OpenAPI Vapor project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of Swift OpenAPI Vapor project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
 import PackageDescription
 
+// General Swift-settings for all targets.
+let swiftSettings: [SwiftSetting] = [
+    // https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md
+    // Require `any` for existential types.
+    .enableUpcomingFeature("ExistentialAny")
+]
+
 let package = Package(
     name: "swift-openapi-vapor",
     platforms: [
@@ -23,14 +42,16 @@ let package = Package(
             dependencies: [
                 .product(name: "Vapor", package: "vapor"),
                 .product(name: "OpenAPIRuntime", package: "swift-openapi-runtime")
-            ]
+            ],
+            swiftSettings: swiftSettings
         ),
         .testTarget(
             name: "OpenAPIVaporTests",
             dependencies: [
                 "OpenAPIVapor",
                 .product(name: "XCTVapor", package: "vapor")
-            ]
+            ],
+            swiftSettings: swiftSettings
         )
     ]
 )
diff --git a/Sources/OpenAPIVapor/VaporTransport.swift b/Sources/OpenAPIVapor/VaporTransport.swift
index 38dc128..965fe38 100644
--- a/Sources/OpenAPIVapor/VaporTransport.swift
+++ b/Sources/OpenAPIVapor/VaporTransport.swift
@@ -20,11 +20,11 @@ import NIOFoundationCompat
 public final class VaporTransport {
 
     /// A routes builder with which to register request handlers.
-    internal var routesBuilder: Vapor.RoutesBuilder
+    internal var routesBuilder: any Vapor.RoutesBuilder
 
     /// Creates a new transport.
     /// - Parameter routesBuilder: A routes builder with which to register request handlers.
-    public init(routesBuilder: Vapor.RoutesBuilder) {
+    public init(routesBuilder: any Vapor.RoutesBuilder) {
         self.routesBuilder = routesBuilder
     }
 }