diff --git a/.builds/debian.yml b/.builds/debian.yml
index 612220f..305d222 100644
--- a/.builds/debian.yml
+++ b/.builds/debian.yml
@@ -1,7 +1,7 @@
-image: debian/bullseye
+image: debian/bookworm
 
 packages:
-  - golang-1.19
+  - golang-1.21
   # The following copied as-is from https://ebiten.org/documents/install.html
   - libc6-dev
   - libglu1-mesa-dev
@@ -15,12 +15,12 @@ packages:
   - pkg-config
 
 repositories:
-  backports: http://deb.debian.org/debian bullseye-backports main
+  backports: http://deb.debian.org/debian bookworm-backports main
 
 tasks:
   - build: |
       cd shark
-      export PATH="$PATH:/usr/lib/go-1.19/bin"
+      export PATH="$PATH:/usr/lib/go-1.21/bin"
       go version
       make linux
       make windows
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b073071..e0d90a2 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -12,7 +12,7 @@ jobs:
     - uses: actions/checkout@v3
     - uses: actions/setup-go@v3
       with:
-        go-version: 1.19
+        go-version: 1.21
 
     - name: Install ebiten linux deps
       run: make deps-debian
@@ -62,7 +62,7 @@ jobs:
     - uses: actions/checkout@v3
     - uses: actions/setup-go@v3
       with:
-        go-version: 1.19
+        go-version: 1.21
 
     - name: Install ebiten linux deps
       run: make deps-debian
@@ -105,7 +105,7 @@ jobs:
     - uses: actions/checkout@v3
     - uses: actions/setup-go@v3
       with:
-        go-version: 1.19
+        go-version: 1.21
 
     - name: Build for macOS
       env: