diff --git a/.bundle/config b/.bundle/config
new file mode 100644
index 0000000..2369228
--- /dev/null
+++ b/.bundle/config
@@ -0,0 +1,2 @@
+---
+BUNDLE_PATH: "vendor/bundle"
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 6af98ca..58302df 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -6,19 +6,19 @@ on:
 name: ci
 jobs:
   build:
-    runs-on: ubuntu-16.04
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         ruby: [ '2.6' ]
     name: Ruby ${{ matrix.ruby }} test
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-ruby@v1
+      - uses: actions/checkout@v6
+      - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
       - name: Build and test
         run: |
-          gem install bundler
+          gem install bundler -v 2.4.22
           bundle install
           bundle exec jekyll build
           bundle exec htmlproofer ./_site --only-4xx --check-favicon --check-html
diff --git a/.gitignore b/.gitignore
index 9132cf4..0f607d1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,4 @@ _site
 node_modules/
 tmp
 .jekyll-cache
-
+vendor/bundle/
diff --git a/Gemfile b/Gemfile
index 6047f7d..e180288 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,6 +1,9 @@
 source "http://rubygems.org"
 
-gem 'json', github: 'flori/json', branch: 'v1.8'
+gem 'json', git: 'https://github.com/ruby/json.git', branch: 'v1.8'
 gem 'jekyll', '4.0.1'
 gem 'jekyll-redirect-from'
 gem 'html-proofer'
+# pin ffi past 1.13.1: that version can't resolve size_t against modern Xcode CLT libffi headers
+# (capped below 1.16 since this project still runs on Ruby 2.6, which newer ffi releases dropped support for)
+gem 'ffi', '~> 1.15.5'
diff --git a/Gemfile.lock b/Gemfile.lock
index e43edec..a09b1ea 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,5 +1,5 @@
 GIT
-  remote: git://github.com/flori/json.git
+  remote: https://github.com/ruby/json.git
   revision: 7f4cfd853f2c919d854fb95548a19980feff17e8
   branch: v1.8
   specs:
@@ -18,7 +18,7 @@ GEM
     ethon (0.12.0)
       ffi (>= 1.3.0)
     eventmachine (1.2.7)
-    ffi (1.13.1)
+    ffi (1.15.5)
     forwardable-extended (2.6.0)
     html-proofer (3.15.3)
       addressable (~> 2.3)
@@ -90,6 +90,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  ffi (~> 1.15.5)
   html-proofer
   jekyll (= 4.0.1)
   jekyll-redirect-from
diff --git a/_layouts/docs.html b/_layouts/docs.html
index 1824d04..f816c46 100644
--- a/_layouts/docs.html
+++ b/_layouts/docs.html
@@ -28,40 +28,24 @@
 
     <!-- Initializer -->
     <script>
-      // use a service to wrap registry json in jsonp
-      var svcs = ['https://json2jsonp.com/', 'https://jsonp.afeld.me/']
-      var i = 0
-      var nextSvc = function () {
-        var svc = svcs[i++]
-        if (!svc) {
-          // no jsonp services worked, just use master
-          console.log('falling back to master branch :(')
-          return Flatdoc.run({
+      // registry.npmjs.org supports CORS, so we can fetch it directly
+      fetch('https://registry.npmjs.org/yargs')
+        .then(function (res) { return res.json() })
+        .then(function (data) {
+          var version = data['dist-tags'] && data['dist-tags'].latest
+          if (!version) throw new Error('no latest version found')
+          console.log('determined latest version as %s', version)
+          Flatdoc.run({
+            fetcher: Flatdoc.file('https://raw.githubusercontent.com/yargs/yargs/v' + version + '/docs/api.md')
+          })
+        })
+        .catch(function (err) {
+          // fall back to master branch if the registry lookup fails
+          console.log('falling back to master branch :(', err)
+          Flatdoc.run({
             fetcher: Flatdoc.github('yargs/yargs', 'docs/api.md')
           })
-        }
-        $.ajax(svc, {
-          data: {
-            url: 'https://registry.npmjs.org/yargs'
-          },
-          dataType: 'jsonp',
-          timeout: 2000,
-          jsonpCallback: svc.replace(/\W/g, ''),
-          success: function (data) {
-            var version = data['dist-tags'] && data['dist-tags'].latest
-            if (!version) return nextSvc()
-            console.log('determined latest version as %s via %s', version, svc)
-            Flatdoc.run({
-              fetcher: Flatdoc.file('https://raw.githubusercontent.com/yargs/yargs/v' + version + '/docs/api.md')
-            })
-          },
-          error: function () {
-            console.log('service failed: %s, trying next', svc)
-            nextSvc()
-          }
         })
-      }
-      nextSvc()
     </script>
   </head>
   <body role='flatdoc' class='no-literate'>