diff --git a/.github/workflows/go-test.yml b/.github/workflows/go-test.yml
index 39f2240..0bda007 100644
--- a/.github/workflows/go-test.yml
+++ b/.github/workflows/go-test.yml
@@ -12,7 +12,7 @@ on:
         type: string
       go-versions:
         description: 'Stringfied JSON object listing target Go versions'
-        default: '["1.21.x", "1.20.x"]'
+        default: '["1.22.x", "1.21.x"]'
         required: false
         type: string
       pre:
diff --git a/.github/workflows/goreleaser.yml b/.github/workflows/goreleaser.yml
index f88194d..3b7e620 100644
--- a/.github/workflows/goreleaser.yml
+++ b/.github/workflows/goreleaser.yml
@@ -4,10 +4,7 @@ on:
   workflow_call:
     inputs:
       go-version:
-        # TODO: upgrade default Go version after 2023-11-01.
-        # Go 1.21 requires Windows Server 2016 or higher.
-        # But Mackerel supports older Windows Servers yet.
-        default: '1.20'
+        default: '1.22'
         required: false
         type: string
 
@@ -27,4 +24,3 @@ jobs:
         args: release --rm-dist
       env:
         GITHUB_TOKEN: ${{ github.token }}
-
diff --git a/.github/workflows/setup-go-matrix.yml b/.github/workflows/setup-go-matrix.yml
index 440a128..a1b920b 100644
--- a/.github/workflows/setup-go-matrix.yml
+++ b/.github/workflows/setup-go-matrix.yml
@@ -13,7 +13,7 @@ on:
         type: string
       go-versions:
         description: 'Stringfied JSON object listing target Go versions'
-        default: '["1.21.x", "1.20.x"]'
+        default: '["1.22.x", "1.21.x"]'
         required: false
         type: string
       run: