diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3a37326..dd86475 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,7 +19,7 @@ jobs:
   run-tests:
     strategy:
       matrix:
-        swift-version: [5.3, 5.4, 5.5, 5.6]
+        swift-version: [5.6, 5.7, 5.8, 5.9]
     runs-on: ubuntu-20.04
     steps:
       - uses: fwal/setup-swift@v1
diff --git a/Package.swift b/Package.swift
index 3434b07..bf4aa0c 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.3
+// swift-tools-version:5.6
 
 // Copyright Dave Verwer, Sven A. Schmidt, and other contributors.
 //