diff --git a/.github/workflows/integration.yml b/.github/workflows/integration.yml
index 98c12d5..d852daa 100644
--- a/.github/workflows/integration.yml
+++ b/.github/workflows/integration.yml
@@ -137,3 +137,43 @@ jobs:
           [[ "$(go version)" == *"1.13"* ]]
           [[ '${{steps.setup_go_1_13_x.outputs.GOROOT}}' == *"1.13"* ]]
           [[ '${{steps.setup_go_1_13_x.outputs.GOTOOLDIR}}' == *"1.13"* ]]
+
+      - id: setup_go_1_21
+        name: install 1.21
+        uses: ./
+        with:
+          go-version: '1.21'
+          ignore-local: true
+          debug: true
+      - name: outputs
+        run: |
+          echo '*********** env ************'
+          env
+          echo '*********** go env ***********'
+          go env
+          echo '${{ toJson( steps.setup_go_1_21.outputs ) }}' | jq .
+          go version
+          set -ex
+          [[ "$(go version)" == *"1.21.0"* ]]
+          [[ '${{steps.setup_go_1_21.outputs.GOROOT}}' == *"1.21.0"* ]]
+          [[ '${{steps.setup_go_1_21.outputs.GOTOOLDIR}}' == *"1.21.0"* ]]
+
+      - id: setup_go_1_21_0
+        name: install 1.21.0
+        uses: ./
+        with:
+          go-version: '1.21.0'
+          ignore-local: true
+          debug: true
+      - name: outputs
+        run: |
+          echo '*********** env ************'
+          env
+          echo '*********** go env ***********'
+          go env
+          echo '${{ toJson( steps.setup_go_1_21.outputs ) }}' | jq .
+          go version
+          set -ex
+          [[ "$(go version)" == *"1.21.0"* ]]
+          [[ '${{steps.setup_go_1_21.outputs.GOROOT}}' == *"1.21.0"* ]]
+          [[ '${{steps.setup_go_1_21.outputs.GOTOOLDIR}}' == *"1.21.0"* ]]
\ No newline at end of file
diff --git a/README.md b/README.md
index 9e91cd8..22dfc40 100644
--- a/README.md
+++ b/README.md
@@ -4,16 +4,11 @@ It's like actions/setup-go but faster.
 
 ## A Note About Go 1.21.0
 
-**Use setup-go-faster@v1.9.0 or later** if you want to install Go 1.21.0.
+**Use setup-go-faster@v1.9.1 or later** if you want to install Go 1.21.0.
 
-With the release of go1.21.0, the Go team has changed the way they publish
-dot-zero releases. They used to be styles go1.N, but now that are go1.N.0. This
-caused issues with earlier versions of setup-go-faster.
-
-**Do not user go-version: 1.21**. Use `go-version: 1.21.0`
-or `go-version: 1.21.x` instead.
-
-I should fix these inconsistencies soon.
+With the release of go1.21.0, the Go team has changed the way they style
+dot-zero releases. They used to be styled like `go1.N`, but now they are 
+`go1.N.0`. This caused issues with earlier versions of setup-go-faster.
 
 ### Faster
 
diff --git a/action.yml b/action.yml
index 43a09ff..08fc1c1 100644
--- a/action.yml
+++ b/action.yml
@@ -69,9 +69,9 @@ runs:
     - id: run
       working-directory: ${{ github.action_path }}
       env:
-        DEBUG: ""
         IGNORE_LOCAL_GO: ${{ inputs.ignore-local }}
         GO_VERSION: ${{ inputs.go-version }}
+        DEBUG: ""
       shell: bash
       run: src/run
 branding:
diff --git a/bindown.yml b/bindown.yml
index 664c5b8..aca16f2 100644
--- a/bindown.yml
+++ b/bindown.yml
@@ -1,6 +1,6 @@
 systems:
-- darwin/amd64
-- linux/amd64
+  - darwin/amd64
+  - linux/amd64
 dependencies:
   action-doc:
     template: action-doc#action-doc
@@ -16,7 +16,7 @@ dependencies:
     vars:
       version: 3.1.0
     required_vars:
-    - version
+      - version
   shellcheck:
     template: origin#shellcheck
     vars:
@@ -27,39 +27,37 @@ dependencies:
     vars:
       ref: ebc4baa08f045b7ef0f45c4b7d6f34f08d732f3d
     required_vars:
-    - ref
+      - ref
 templates:
   action-doc#action-doc:
     url: https://github.com/WillAbides/action-doc/releases/download/v{{.version}}/action-doc_{{.version}}_{{.os}}_{{.arch}}.tar.gz
-    required_vars:
-    - version
     systems:
-    - darwin/amd64
-    - linux/386
-    - linux/amd64
+      - darwin/amd64
+      - linux/386
+      - linux/amd64
+    required_vars:
+      - version
   origin#octo:
     url: https://github.com/octo-cli/octo-cli/releases/download/v{{.version}}/octo-cli_{{.version}}_{{.os}}_{{.arch}}.tar.gz
     archive_path: octo{{.archivepathsuffix}}
     bin: octo
     vars:
       archivepathsuffix: ""
-    required_vars:
-    - version
     overrides:
-    - matcher:
-        os:
-        - windows
-      dependency:
-        vars:
-          archivepathsuffix: .exe
-    - matcher:
-        arch:
-        - arm64
-        os:
-        - darwin
-      dependency:
-        vars:
-          arch: amd64
+      - matcher:
+          os:
+            - windows
+        dependency:
+          vars:
+            archivepathsuffix: .exe
+      - matcher:
+          arch:
+            - arm64
+          os:
+            - darwin
+        dependency:
+          vars:
+            arch: amd64
     substitutions:
       arch:
         "386": i386
@@ -69,33 +67,35 @@ templates:
         linux: Linux
         windows: Windows
     systems:
-    - darwin/386
-    - darwin/amd64
-    - darwin/arm64
-    - linux/386
-    - linux/amd64
-    - windows/386
-    - windows/amd64
+      - darwin/386
+      - darwin/amd64
+      - darwin/arm64
+      - linux/386
+      - linux/amd64
+      - windows/386
+      - windows/amd64
+    required_vars:
+      - version
   origin#shellcheck:
     url: https://github.com/koalaman/shellcheck/releases/download/v{{.version}}/shellcheck-v{{.version}}.{{.os}}.{{.arch}}.tar.xz
     archive_path: shellcheck-v{{.version}}/shellcheck
     bin: shellcheck
-    required_vars:
-    - version
     overrides:
-    - matcher:
-        os:
-        - windows
-      dependency:
-        url: https://github.com/koalaman/shellcheck/releases/download/v{{.version}}/shellcheck-v{{.version}}.zip
-        archive_path: shellcheck-v{{.version}}.exe
+      - matcher:
+          os:
+            - windows
+        dependency:
+          url: https://github.com/koalaman/shellcheck/releases/download/v{{.version}}/shellcheck-v{{.version}}.zip
+          archive_path: shellcheck-v{{.version}}.exe
     substitutions:
       arch:
         amd64: x86_64
     systems:
-    - darwin/amd64
-    - linux/amd64
-    - windows/amd64
+      - darwin/amd64
+      - linux/amd64
+      - windows/amd64
+    required_vars:
+      - version
 template_sources:
   action-doc: https://raw.githubusercontent.com/WillAbides/action-doc/main/bindown.yml
   origin: https://raw.githubusercontent.com/WillAbides/bindown-templates/master/bindown.yml
diff --git a/script/bindown b/script/bindown
index 6d225db..fb11d9d 100755
--- a/script/bindown
+++ b/script/bindown
@@ -6,6 +6,6 @@ CDPATH="" cd -- "$(dirname -- "$(dirname -- "$0")")"
 
 mkdir -p bin
 
-[ -f bin/bindown ] || sh -c "$(curl -sfL https://github.com/WillAbides/bindown/releases/download/v3.10.1/bootstrap-bindown.sh)"
+[ -f bin/bindown ] || sh -c "$(curl -sfL https://github.com/WillAbides/bindown/releases/download/v4.6.0/bootstrap-bindown.sh)"
 
 exec bin/bindown "$@"
diff --git a/src/lib b/src/lib
index 2d381b3..edcfaad 100755
--- a/src/lib
+++ b/src/lib
@@ -72,6 +72,7 @@ download_go_url() {
 install_go() {
   local go_version="$1"
   local target_dir="$2"
+  debug_out "installing go $go_version to $target_dir"
   rm -rf "$target_dir"
   mkdir -p "$(dirname "$target_dir")"
   tmpdir="$(init_tmpdir)"
@@ -113,8 +114,9 @@ exe_name() {
 }
 
 is_precise_version() {
-  [[ $1 =~ ^[0-9]+(.[0-9]+(.[0-9]+)?)?([A-Za-z0-9]+)?$ ]] && return
-  return 1
+  [[ $1 =~ ^[0-9]+(.([0-9]+)(.[0-9]+)?)?([A-Za-z0-9]+)?$ ]] || return 1
+  # false when minor is >= 21 and patch is empty
+  [ -z "${BASH_REMATCH[2]}" ] || [ "${BASH_REMATCH[2]}" -lt 21 ] || [ -n "${BASH_REMATCH[3]}" ]
 }
 
 select_go_version() {
diff --git a/src/lib_test.sh b/src/lib_test.sh
index 56f9c2f..16c3a39 100755
--- a/src/lib_test.sh
+++ b/src/lib_test.sh
@@ -40,6 +40,8 @@ test_is_precise_version() {
 9999.9999.9999
 1.15beta1
 1.16rc1
+1.21.0
+1.21.1
   '
 
   for v in $versions; do
@@ -48,6 +50,7 @@ test_is_precise_version() {
   done
 
   not_versions='
+1.21
 *
 1.x
 1.15.x