diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index ed4b1e520b..b7fe63572b 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -12,7 +12,7 @@
       "version": "latest"
     },
     "ghcr.io/devcontainers/features/ruby:1": {
-      "version": "3.3.6"
+      "version": "3.1.4"
     },
     "ghcr.io/devcontainers/features/node:1": {
       "version": "18.16"
diff --git a/.ruby-version b/.ruby-version
index 9c25013dbb..0aec50e6ed 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-3.3.6
+3.1.4
diff --git a/.tool-versions b/.tool-versions
index 3a396fea2d..7fef5f5899 100644
--- a/.tool-versions
+++ b/.tool-versions
@@ -1,2 +1,2 @@
 terraform 1.5.4
-ruby      3.3.6
+ruby      3.1.4
diff --git a/Dockerfile b/Dockerfile
index 4e6051a1f5..122eb1601f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 # To use or update to a ruby version, change BASE_RUBY_IMAGE
-ARG BASE_RUBY_IMAGE=ruby:3.3.6-alpine3.20
+ARG BASE_RUBY_IMAGE=ruby:3.1.4-alpine3.18
 
 FROM ${BASE_RUBY_IMAGE} AS base
 
diff --git a/Gemfile b/Gemfile
index 9968bd758c..2602de4c44 100644
--- a/Gemfile
+++ b/Gemfile
@@ -134,12 +134,13 @@ group :development, :test do
 
   # Testing framework
   gem "knapsack"
-  gem "rspec-rails", "~> 7.1.0"
+  gem "rspec-rails", "~> 6.0.3"
 
   # Adds support for Capybara system testing and selenium driver
   gem "capybara", "~> 3.40.0"
   gem "factory_bot_rails", ">= 6.2.0"
-  gem "rspec-sonarqube-formatter", "~> 1.6.1", require: false
+  # See: https://github.com/otherguy/rspec-sonarqube-formatter/pull/63
+  gem "rspec-sonarqube-formatter", github: "otherguy/rspec-sonarqube-formatter", ref: "13fe436", require: false
   gem "simplecov"
 
   # Linting
diff --git a/Gemfile.lock b/Gemfile.lock
index 12431de7d4..6ca8f91823 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -68,6 +68,15 @@ GIT
       activemodel (>= 6.0.0, < 7.1)
       timeliness (>= 0.3.10, < 1)
 
+GIT
+  remote: https://github.com/otherguy/rspec-sonarqube-formatter.git
+  revision: 13fe436921e1442a09c23d9e46055773d1511638
+  ref: 13fe436
+  specs:
+    rspec-sonarqube-formatter (1.0.0.pre.local)
+      htmlentities (~> 4.3.3)
+      rspec (~> 3.0)
+
 GIT
   remote: https://github.com/pkorenev/rack-page_caching.git
   revision: 9ca404f7f7e4773030e75799da7ab02e27cbe9a3
@@ -196,7 +205,7 @@ GEM
     csv (3.3.0)
     declarative (0.0.20)
     delegate (0.3.1)
-    diff-lcs (1.5.1)
+    diff-lcs (1.5.0)
     docile (1.4.0)
     dotenv (3.1.2)
     dotenv-rails (3.1.2)
@@ -391,10 +400,10 @@ GEM
     net-smtp (0.5.0)
       net-protocol
     nio4r (2.7.3)
-    nokogiri (1.16.7)
+    nokogiri (1.16.5)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    nokogiri (1.16.7-x86_64-linux)
+    nokogiri (1.16.5-x86_64-linux)
       racc (~> 1.4)
     observer (0.1.1)
     os (1.1.4)
@@ -488,32 +497,29 @@ GEM
     rexml (3.3.3)
       strscan
     rinku (2.0.6)
-    rspec (3.13.0)
-      rspec-core (~> 3.13.0)
-      rspec-expectations (~> 3.13.0)
-      rspec-mocks (~> 3.13.0)
-    rspec-core (3.13.2)
-      rspec-support (~> 3.13.0)
-    rspec-expectations (3.13.3)
+    rspec (3.12.0)
+      rspec-core (~> 3.12.0)
+      rspec-expectations (~> 3.12.0)
+      rspec-mocks (~> 3.12.0)
+    rspec-core (3.12.0)
+      rspec-support (~> 3.12.0)
+    rspec-expectations (3.12.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.13.0)
-    rspec-mocks (3.13.2)
+      rspec-support (~> 3.12.0)
+    rspec-mocks (3.12.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.13.0)
-    rspec-rails (7.1.0)
-      actionpack (>= 7.0)
-      activesupport (>= 7.0)
-      railties (>= 7.0)
-      rspec-core (~> 3.13)
-      rspec-expectations (~> 3.13)
-      rspec-mocks (~> 3.13)
-      rspec-support (~> 3.13)
+      rspec-support (~> 3.12.0)
+    rspec-rails (6.0.3)
+      actionpack (>= 6.1)
+      activesupport (>= 6.1)
+      railties (>= 6.1)
+      rspec-core (~> 3.12)
+      rspec-expectations (~> 3.12)
+      rspec-mocks (~> 3.12)
+      rspec-support (~> 3.12)
     rspec-retry (0.6.2)
       rspec-core (> 3.3)
-    rspec-sonarqube-formatter (1.6.1)
-      htmlentities (~> 4.3)
-      rspec (~> 3.0)
-    rspec-support (3.13.1)
+    rspec-support (3.12.0)
     rubocop (1.64.1)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
@@ -632,7 +638,7 @@ GEM
     websocket-extensions (0.1.5)
     xpath (3.2.0)
       nokogiri (~> 1.8)
-    zeitwerk (2.7.1)
+    zeitwerk (2.6.18)
 
 PLATFORMS
   ruby
@@ -700,9 +706,9 @@ DEPENDENCIES
   redis-session-store (>= 0.11.4)
   rexml (>= 3.2.5)
   rinku
-  rspec-rails (~> 7.1.0)
+  rspec-rails (~> 6.0.3)
   rspec-retry
-  rspec-sonarqube-formatter (~> 1.6.1)
+  rspec-sonarqube-formatter!
   rubocop-govuk (~> 5.0.2)
   secure_headers
   selenium-webdriver (~> 4.21.1)
@@ -726,7 +732,7 @@ DEPENDENCIES
   webmock (>= 3.14.0)
 
 RUBY VERSION
-   ruby 3.3.6
+   ruby 3.1.4p223
 
 BUNDLED WITH
    2.3.4
diff --git a/config/application.rb b/config/application.rb
index 3e3754335b..32186bad84 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -19,9 +19,6 @@
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
 
-# Patch to Rack::PageCaching::Utils to substitute Fixnum --> Integer
-require_relative "../lib/patch_rack_page_caching"
-
 module GetIntoTeachingWebsite
   class Application < Rails::Application
     # Initialize configuration defaults for originally generated Rails version.
diff --git a/config/environments/development.rb b/config/environments/development.rb
index 02ac88d6d8..49f741adf6 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -72,5 +72,5 @@
   config.x.dfe_analytics = true
 
   # Allow access from Codespaces
-  config.hosts << /[a-z0-9-]+\.((preview\.)?app\.github|githubpreview)\.dev/
+  config.hosts << /[a-z0-9-]+\.(preview\.app\.github|githubpreview)\.dev/
 end
diff --git a/lib/patch_rack_page_caching.rb b/lib/patch_rack_page_caching.rb
deleted file mode 100644
index aca69ea86d..0000000000
--- a/lib/patch_rack_page_caching.rb
+++ /dev/null
@@ -1,19 +0,0 @@
-# NB: we are using a very old gem (https://github.com/pkorenev/rack-page_caching)
-# which requires the deprecated Fixnum class - this is a patch to switch Fixnum --> Integer
-
-module Rack
-  class PageCaching
-    module Utils
-      def self.gzip_level(gzip)
-        case gzip
-        when Symbol
-          Zlib.const_get(gzip.to_s.upcase)
-        when Integer
-          gzip
-        else
-          false
-        end
-      end
-    end
-  end
-end
diff --git a/spec/capybara_driver_helper.rb b/spec/capybara_driver_helper.rb
index 05769f81e0..ac3817a117 100644
--- a/spec/capybara_driver_helper.rb
+++ b/spec/capybara_driver_helper.rb
@@ -23,10 +23,6 @@
 Capybara.default_max_wait_time = 2
 RSpec.configure do |config|
   config.before do |example|
-    if example.metadata[:js]
-      raise NotImplementedError, "The Capybara driver #{JS_DRIVER} is not currently supported in Alpine 3.20. Please use the default :rack_test driver instead and test javascript behaviour in js-spec tests"
-    end
-
     Capybara.current_driver = JS_DRIVER if example.metadata[:js]
     Capybara.current_driver = :selenium if example.metadata[:selenium]
     Capybara.current_driver = :selenium_chrome if example.metadata[:selenium_chrome]
diff --git a/spec/features/chat_spec.rb b/spec/features/chat_spec.rb
index 5dd270a70a..024d92bb6c 100644
--- a/spec/features/chat_spec.rb
+++ b/spec/features/chat_spec.rb
@@ -6,39 +6,57 @@
   before do
     allow(ENV).to receive(:fetch).and_call_original
     allow(ENV).to receive(:fetch).with("CHAT_AVAILABILITY_API", nil).and_return("http://api.example/")
+    stub_request(:get, "http://api.example/")
+      .to_return(status: 200, body: "{\"skillid\": 123456, \"available\": false, \"status_age\": 123 }")
   end
 
-  context "when agents are available" do
-    before do
-      stub_request(:get, "http://api.example/")
-        .to_return(status: 200, body: "{\"skillid\": 123456,	\"available\": true, \"status_age\": 123 }")
-    end
+  context "when javascript is enabled", :js do
+    context "when agents are available" do
+      before do
+        stub_request(:get, "http://api.example/")
+          .to_return(status: 200, body: "{\"skillid\": 123456,	\"available\": true, \"status_age\": 123 }")
+      end
 
-    scenario "viewing the chat section of the talk to us component" do
-      visit root_path
-      dismiss_cookies
+      scenario "viewing the chat section of the talk to us component" do
+        visit root_path
+        dismiss_cookies
 
-      within(".talk-to-us") do
-        click_link("Open chat in new tab")
-      end
+        within(".talk-to-us") do
+          click_link("Open chat in new tab")
+        end
 
-      expect(page.driver.current_url).to end_with("/chat#root")
-      expect(page).to have_css("#root", visible: false)
+        popup_window_handle = (page.driver.browser.window_handles - [page.driver.current_window_handle]).first
+        page.driver.switch_to_window(popup_window_handle)
+        expect(page.driver.current_url).to end_with("/chat")
+        expect(page).to have_css("#root", visible: false)
+        page.driver.close_window(popup_window_handle)
+      end
     end
-  end
 
-  context "when agents are not available" do
-    before do
-      stub_request(:get, "http://api.example/")
-        .to_return(status: 200, body: "{\"skillid\": 123456, \"available\": false, \"status_age\": 123 }")
+    context "when agents are not available" do
+      before do
+        stub_request(:get, "http://api.example/")
+          .to_return(status: 200, body: "{\"skillid\": 123456,	\"available\": false, \"status_age\": 123 }")
+      end
+
+      scenario "viewing the chat section of the talk to us component" do
+        visit root_path
+        dismiss_cookies
+
+        within(".talk-to-us") do
+          expect(page).to have_text("Chat is closed")
+        end
+      end
     end
+  end
 
+  context "when javascript is not enabled", js: false do
     scenario "viewing the chat section of the talk to us component" do
       visit root_path
       dismiss_cookies
 
       within(".talk-to-us") do
-        expect(page).to have_text("Chat is closed")
+        expect(page).to have_text("Chat not available")
       end
     end
   end
@@ -46,4 +64,8 @@
   def dismiss_cookies
     click_link "Accept all cookies"
   end
+
+  def visit_on_date(path)
+    visit "#{path}?fake_browser_time=#{date.to_i * 1000}"
+  end
 end
diff --git a/spec/javascript/controllers/chat_controller_spec.js b/spec/javascript/controllers/chat_controller_spec.js
index 6017ae0a53..f0953fbd52 100644
--- a/spec/javascript/controllers/chat_controller_spec.js
+++ b/spec/javascript/controllers/chat_controller_spec.js
@@ -78,4 +78,5 @@ describe('ChatController', () => {
       })
     });
   });
+
 });