diff --git a/Package.swift b/Package.swift
index 960e3311..f8045977 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version: 5.8
+// swift-tools-version: 5.9
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the SwiftOpenAPIGenerator open source project
@@ -15,15 +15,11 @@
 import PackageDescription
 
 // General Swift-settings for all targets.
-var swiftSettings: [SwiftSetting] = []
-
-#if swift(>=5.9)
-swiftSettings.append(
+let swiftSettings: [SwiftSetting] = [
     // https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md
     // Require `any` for existential types.
     .enableUpcomingFeature("ExistentialAny")
-)
-#endif
+]
 
 let package = Package(
     name: "swift-openapi-runtime",
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 76bb652d..5040ad9c 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,4 +1,4 @@
-ARG swift_version=5.8
+ARG swift_version=5.9
 ARG ubuntu_version=jammy
 ARG base_image=swift:${swift_version}-${ubuntu_version}
 
diff --git a/docker/docker-compose.2204.58.yaml b/docker/docker-compose.2204.58.yaml
deleted file mode 100644
index 071d15ba..00000000
--- a/docker/docker-compose.2204.58.yaml
+++ /dev/null
@@ -1,19 +0,0 @@
-version: "3"
-
-services:
-  runtime-setup:
-    image: &image swift-openapi-runtime:22.04-5.8
-    build:
-      args:
-        ubuntu_version: "jammy"
-        swift_version: "5.8"
-
-  test:
-    image: *image
-    environment:
-      - WARN_AS_ERROR_ARG=-Xswiftc -warnings-as-errors
-      - IMPORT_CHECK_ARG=--explicit-target-dependency-import-check error
-      - STRICT_CONCURRENCY_ARG=-Xswiftc -strict-concurrency=complete
-
-  shell:
-    image: *image
diff --git a/docker/docker-compose.yaml b/docker/docker-compose.yaml
index 000a5ad0..c63046bb 100644
--- a/docker/docker-compose.yaml
+++ b/docker/docker-compose.yaml
@@ -4,7 +4,7 @@
 #
 # % docker-compose \
 #   -f docker/docker-compose.yaml \
-#   -f docker/docker-compose.2204.58.yaml \
+#   -f docker/docker-compose.2204.59.yaml \
 #   run test
 #
 version: "3"