diff --git a/.github/workflows/benchmarks.yml b/.github/workflows/benchmarks.yml
index 3f709e1d..9a2e03bd 100644
--- a/.github/workflows/benchmarks.yml
+++ b/.github/workflows/benchmarks.yml
@@ -17,7 +17,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '1.20.x'
+          go-version: '1.21.x'
       - name: Install dependencies
         run: go get .
       - name: Run internal benchmarks
@@ -36,7 +36,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '1.20.x'
+          go-version: '1.21.x'
       - name: Install dependencies
         run: go get .
       - name: Benchmark vs. Array of Structs
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6852da40..4fd42d25 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -18,7 +18,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '1.20.x'
+          go-version: '1.21.x'
       - name: Install dependencies
         run: go get .
       - name: Build Linux
@@ -35,7 +35,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v2
       with:
-        go-version: '1.20.x'
+        go-version: '1.21.x'
     - name: Check out code
       uses: actions/checkout@v2
     - name: Install dependencies
@@ -58,7 +58,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '1.20.x'
+          go-version: '1.21.x'
       - name: Install dependencies
         run: |
           go get .
@@ -84,7 +84,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '1.20.x'
+          go-version: '1.21.x'
       - name: Install dependencies
         run: |
           go get .
@@ -103,7 +103,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '1.20.x'
+          go-version: '1.21.x'
       - name: Install dependencies
         run: go get .
       - name: Run examples
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c799af6b..916d5a1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [[v0.9.0]](https://github.com/mlange-42/arche/compare/v0.8.1...v0.9.0)
+
+### Infrastructure
+
+* Upgraded to Go 1.21 toolchain (#308)
+
 ## [[v0.8.1]](https://github.com/mlange-42/arche/compare/v0.8.0...v0.8.1)
 
 ### Documentation
diff --git a/benchmark/go.mod b/benchmark/go.mod
index cef2e7f7..a079019d 100644
--- a/benchmark/go.mod
+++ b/benchmark/go.mod
@@ -1,6 +1,8 @@
 module github.com/mlange-42/arche/benchmark
 
-go 1.20
+go 1.21
+
+toolchain go1.21.3
 
 require (
 	github.com/marioolofo/go-gameengine-ecs v0.9.0
diff --git a/benchmark/go.sum b/benchmark/go.sum
index 9a090383..f6d38971 100644
--- a/benchmark/go.sum
+++ b/benchmark/go.sum
@@ -22,6 +22,7 @@ github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
+github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/wfranczyk/ento v0.1.0 h1:BMuty7VOn8qNp7EbUhlimQXnckuwrjuJSgJ46NFdk2E=
 github.com/wfranczyk/ento v0.1.0/go.mod h1:oiJdFEvu66RU8kZwEySB/xfizPLQ/maChXwYPxY3l9o=
 github.com/yohamta/donburi v1.3.4 h1:u/Wa+JA9/c/73J9eAvUZgomvbhpl0jZXagM4sjSNImw=
diff --git a/go.mod b/go.mod
index 9d19de2f..81f916dd 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,8 @@
 module github.com/mlange-42/arche
 
-go 1.20
+go 1.21
+
+toolchain go1.21.3
 
 require github.com/stretchr/testify v1.8.2
 
diff --git a/go.work b/go.work
index c0d9fee7..4a6ed1ac 100644
--- a/go.work
+++ b/go.work
@@ -1,4 +1,6 @@
-go 1.20
+go 1.21
+
+toolchain go1.21.3
 
 use (
 	.