diff --git a/.bazelversion b/.bazelversion
index ee74734..91ff572 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-4.1.0
+5.2.0
diff --git a/.circleci/Dockerfile b/.circleci/Dockerfile
index cff3ce5..24df40b 100644
--- a/.circleci/Dockerfile
+++ b/.circleci/Dockerfile
@@ -1,7 +1,7 @@
 #
 # rules_ruby circleci Docker file.
 #
-FROM ruby:3.0.2
+FROM ruby:3.1.2
 
 # make Apt non-interactive
 RUN echo 'APT::Get::Assume-Yes "true";' > /etc/apt/apt.conf.d/90circleci \
@@ -92,7 +92,7 @@ RUN apt-get update && apt-get upgrade
 
 RUN apt-get install -y openjdk-11-jdk python2.7 python3 golang-go
 
-RUN curl -L -o /usr/bin/bazel https://github.com/bazelbuild/bazelisk/releases/download/v1.3.0/bazelisk-linux-amd64 \
+RUN curl -L -o /usr/bin/bazel https://github.com/bazelbuild/bazelisk/releases/download/v1.12.0/bazelisk-linux-amd64 \
     && sudo chmod +x /usr/bin/bazel
 
 RUN cd /usr/bin && ln -s python3 python
diff --git a/.circleci/README.md b/.circleci/README.md
new file mode 100644
index 0000000..97bfa5d
--- /dev/null
+++ b/.circleci/README.md
@@ -0,0 +1,14 @@
+## `build.sh`
+
+Anytime you change the Ruby version you must push a new image to Docker Hub.
+
+Email kigster@gmail.com to be added to bazelruby org on hub.docker.com.
+
+### To Upgrade
+
+Change the ruby version in the `Dockerfile` and run:
+
+```bash
+cd .circleci
+./build.sh
+```
diff --git a/.circleci/build.sh b/.circleci/build.sh
index b775eea..9492db6 100755
--- a/.circleci/build.sh
+++ b/.circleci/build.sh
@@ -12,7 +12,7 @@ echo
 
 set -x 
 
-docker build . -t bazelruby/ruby-$RUBY_VERSION
+docker build --platform linux/x86_64 . -t bazelruby/ruby-$RUBY_VERSION
 
 docker push       bazelruby/ruby-$RUBY_VERSION
 
diff --git a/.circleci/config.yml b/.circleci/config.yml
index 5ee0d7e..367abdd 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -5,7 +5,7 @@ jobs:
     working_directory: /home/circleci/repo
     resource_class: medium
     docker:
-      - image: bazelruby/ruby-3.0.2
+      - image: bazelruby/ruby-3.1.2
     environment:
       PATH: "/usr/local/bin:/usr/bin:/sbin:/opt/bin:/home/circleci/repo/bin:/bin:/sbin:/usr/sbin"
       BUNDLE_PATH: /home/circleci/.bundle_cache
diff --git a/.ruby-version b/.ruby-version
index b502146..ef538c2 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.0.2
+3.1.2
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3d1c3af..bc3c466 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Changelog
 
+## [Unreleased](https://github.com/bazelruby/rules_ruby/tree/HEAD)
+
+[Full Changelog](https://github.com/bazelruby/rules_ruby/compare/v0.6.0...HEAD)
+
+**Merged pull requests:**
+
+- Bump nokogiri from 1.13.3 to 1.13.4 in /examples/simple\_rails\_api [\#130](https://github.com/bazelruby/rules_ruby/pull/130) ([dependabot[bot]](https://github.com/apps/dependabot))
+- Bump puma from 4.3.11 to 4.3.12 in /examples/simple\_rails\_api [\#126](https://github.com/bazelruby/rules_ruby/pull/126) ([dependabot[bot]](https://github.com/apps/dependabot))
+- Add SDK versions: 2.6.9,2.7.5,3.0.3,3.1.0,3.1.0 [\#123](https://github.com/bazelruby/rules_ruby/pull/123) ([matsubara0507](https://github.com/matsubara0507))
+- Bump nokogiri from 1.12.5 to 1.13.3 in /examples/simple\_rails\_api [\#122](https://github.com/bazelruby/rules_ruby/pull/122) ([dependabot[bot]](https://github.com/apps/dependabot))
+- Bump puma from 4.3.9 to 4.3.11 in /examples/simple\_rails\_api [\#121](https://github.com/bazelruby/rules_ruby/pull/121) ([dependabot[bot]](https://github.com/apps/dependabot))
+
 ## [v0.6.0](https://github.com/bazelruby/rules_ruby/tree/v0.6.0) (2021-11-09)
 
 [Full Changelog](https://github.com/bazelruby/rules_ruby/compare/v0.5.2...v0.6.0)
diff --git a/README.pdf b/README.pdf
index 87bfb50..2b1a1ed 100644
Binary files a/README.pdf and b/README.pdf differ
diff --git a/WORKSPACE b/WORKSPACE
index e08c5ee..5926be2 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -12,7 +12,7 @@ load("@bazel_skylib//lib:versions.bzl", "versions")
 
 versions.check("3.4.1")
 
-rules_ruby_select_sdk("3.0.2")
+rules_ruby_select_sdk("3.1.2")
 
 local_repository(
     name = "bazelruby_rules_ruby_ruby_tests_testdata_another_workspace",
diff --git a/bin/setup b/bin/setup
index c0799ca..71b8e97 100755
--- a/bin/setup
+++ b/bin/setup
@@ -16,6 +16,8 @@
 
 source "bin/deps"
 
+export ruby_version="$(cat .ruby-version | tr -d '\n')"
+
 #—————————————————————————————————————————————————————————————————————————————————————————————————————————————
 # Private Functions
 #—————————————————————————————————————————————————————————————————————————————————————————————————————————————
@@ -30,8 +32,19 @@ __setup.actions() {
 #—————————————————————————————————————————————————————————————————————————————————————————————————————————————
 
 setup.rbenv() {
+  command -v rbenv >/dev/null || {
+    if [[ $(uname -s) == "Darwin" ]]; then
+      command -v brew>/dev/null || /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
+      brew.install.packages rbenv ruby-build
+      brew.upgrade.packages rbenv ruby-build
+    else
+      setup.local-rbenv
+    fi
+  }
+}
+
+setup.local-rbenv() {
   local rbenv_home="${HOME}/.rbenv"
-  local ruby_version="$(cat .ruby-version | tr -d '\n')"
 
   if [[ -n $(command -v ruby) ]]; then
     local installed_version="$(ruby -e 'puts RUBY_VERSION' | tr -d '\n')"
@@ -65,9 +78,10 @@ setup.rbenv() {
     error "PATH: ${PATH}"
     return 1
   }
+}
 
-  # Set our current ruby version to the desired one, even if it's not yet there.
-  # This allows the next block to auto-detect it and skip the remainder.
+setup.ruby() {
+  run "rbenv install -s ${ruby_version}"
   run "rbenv global ${ruby_version} || true"
   # see if we even need to install anything:
   local ruby_sdk_marker="$(rbenv versions | grep "${ruby_version}" | cut -d ' ' -f 1)"
@@ -171,6 +185,7 @@ setup.main() {
     set +e
     h2 "Installing required development dependencies for working with rules_ruby and Bazel."
     setup.rbenv
+    setup.ruby
     setup.gems
     [[ -z ${CI} ]] && setup.git-hook
     setup.os-specific "$@"
diff --git a/bin/setup-darwin b/bin/setup-darwin
index 3327bb4..eefa38a 100755
--- a/bin/setup-darwin
+++ b/bin/setup-darwin
@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+# vim: ft=bash
 # —————————————————————————————————————————————————————————————————————————————————————
 # NOTE: These setup scripts rely on an open source BASH framework BashMatic.
 #       https://github.com/kigster/bashmatic
@@ -52,15 +53,14 @@ setup.xcode-tools() {
     info: "xcode-select tools are already installed."
   fi
 
-  info "Next command requires sudo privileges to accept XCode License"
-  run.set-next show-output-on
-  run "sudo xcodebuild -license accept"
+  info "Next command may require a sudo privileges to accept XCode License"
+  bin/xcode-accept
 }
 
 setup.bazel() {
   brew.package.is-installed bazelisk && 
-    brew.uninstall.package bazelisk && 
-      run "brew unlink bazel"
+    brew.uninstall.package bazelisk 1>/dev/null 2>/dev/null && 
+      run "brew unlink bazel 2>/dev/null || true"
     
   if __setup.is-bazelisk-installed && __setup.is-bazel-installed ; then
     info: "Bazel & bazelisk are already installed."
@@ -68,8 +68,6 @@ setup.bazel() {
     brew.install.packages bazel bazelisk
     run "brew link bazel || true"
   fi
-
-  
 }
 
 setup.darwin() {
diff --git a/bin/xcode-accept b/bin/xcode-accept
new file mode 100755
index 0000000..ab05ff1
--- /dev/null
+++ b/bin/xcode-accept
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# vim: ft=bash
+
+# https://stackoverflow.com/questions/58632629/how-to-check-if-xcode-license-needs-to-be-accepted
+
+XCODE_VERSION=$(xcodebuild -version | grep '^Xcode\s' | sed -E 's/^Xcode[[:space:]]+([0-9\.]+)/\1/')
+ACCEPTED_LICENSE_VERSION=$(defaults read /Library/Preferences/com.apple.dt.Xcode 2> /dev/null | grep IDEXcodeVersionForAgreedToGMLicense | cut -d '"' -f 2)
+
+if [[ "$XCODE_VERSION" = "$ACCEPTED_LICENSE_VERSION" ]]; then 
+    exit 0
+else
+    exit 1
+fi
diff --git a/examples/simple_rails_api/WORKSPACE b/examples/simple_rails_api/WORKSPACE
index 8585cfe..39e0004 100644
--- a/examples/simple_rails_api/WORKSPACE
+++ b/examples/simple_rails_api/WORKSPACE
@@ -15,7 +15,7 @@ load(
 
 rules_ruby_dependencies()
 
-rules_ruby_select_sdk(version = "3.0.2")
+rules_ruby_select_sdk(version = "3.1.2")
 
 load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
 
diff --git a/examples/simple_script/.ruby-version b/examples/simple_script/.ruby-version
index b502146..ef538c2 100644
--- a/examples/simple_script/.ruby-version
+++ b/examples/simple_script/.ruby-version
@@ -1 +1 @@
-3.0.2
+3.1.2
diff --git a/examples/simple_script/WORKSPACE b/examples/simple_script/WORKSPACE
index 4ad11d1..482d59f 100644
--- a/examples/simple_script/WORKSPACE
+++ b/examples/simple_script/WORKSPACE
@@ -15,7 +15,7 @@ load(
 
 rules_ruby_dependencies()
 
-rules_ruby_select_sdk(version = "3.0.2")
+rules_ruby_select_sdk(version = "3.1.2")
 
 load("@bazelruby_rules_ruby//ruby:defs.bzl", "ruby_bundle")
 
diff --git a/ruby/private/sdk.bzl b/ruby/private/sdk.bzl
index 7123575..ab2ca50 100644
--- a/ruby/private/sdk.bzl
+++ b/ruby/private/sdk.bzl
@@ -28,6 +28,7 @@ def rules_ruby_select_sdk(version = "host"):
         "3.0.3",
         "3.1.0",
         "3.1.1",
+        "3.1.2",
     ]
 
     if version in supported_versions:
diff --git a/ruby/tests/testdata/bundle_includes_workspace/WORKSPACE b/ruby/tests/testdata/bundle_includes_workspace/WORKSPACE
index 00a3bb4..40ff57c 100644
--- a/ruby/tests/testdata/bundle_includes_workspace/WORKSPACE
+++ b/ruby/tests/testdata/bundle_includes_workspace/WORKSPACE
@@ -13,7 +13,7 @@ load(
 
 rules_ruby_dependencies()
 
-rules_ruby_select_sdk(version = "3.0.2")
+rules_ruby_select_sdk(version = "3.1.2")
 
 load("@bazelruby_rules_ruby//ruby:defs.bzl", "ruby_bundle")