diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 8111d46..a74c597 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rails-version: ['5.2.5', '6.0.3.6', '6.1.3.1', '7.0.5', 'main']
+        rails-version: ['5.2.8.1', '6.0.3.7', '6.1.7.6', '7.0.8', '7.1.2', 'main']
         ruby-version: ['2.7', '3.0', '3.1', '3.2']
         exclude:
           - rails-version: '5.2.5'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f67038c..0b2d775 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,7 @@
 
 * Added Ruby 3.0, 3.1, 3.2 to the test matrix.
 
-* Added Rails 6.1.x and 7.0.x to the build matrix.
+* Added Rails 6.1.x, 7.0.x, 7.1.x to the build matrix.
 
 * Dropped support for Rails 4. Going forward we're targetting Rails 5.x (and 6.x). Rails 5 deprecates a few configuration options that we need access to. If you still need support for Rails 4.x, version 1.2.2 of route_downcaser should work just fine.
 
diff --git a/README.rdoc b/README.rdoc
index 9692cb8..c797579 100644
--- a/README.rdoc
+++ b/README.rdoc
@@ -6,7 +6,7 @@ This gem hooks into the Rack middleware of Rails. This way all paths are downcas
 
 == Requirements
 
-This gem is tested with 5.2.x, 6.0.x, 6.1.x. It reportedly also works with Sinatra, although I do not use Sinatra myself. Sinatra test-cases will be most welcome.
+This gem is tested with 5.2.x, 6.0.x, 6.1.x., 7.x. It reportedly also works with Sinatra, although I do not use Sinatra myself. Sinatra test-cases will be most welcome.
 
 It has previously worked - and I presume still works - in Rails 5.0.x and 5.1.x.
 
diff --git a/test.rb b/test.rb
new file mode 100644
index 0000000..792f384
--- /dev/null
+++ b/test.rb
@@ -0,0 +1,103 @@
+# frozen_string_literal: true
+
+gem "activesupport"
+# require 'active_support/all'
+require "route_downcaser"
+require "route_downcaser/downcase_route_middleware"
+require "route_downcaser/original_downcase_route_middleware"
+
+require "benchmark"
+
+class FakeApp
+  def call(env)
+  end
+end
+
+ITERATIONS = 1_000_000
+
+app = FakeApp.new
+original_downcaser = RouteDowncaser::OriginalDowncaseRouteMiddleware.new(app)
+optimized_downcaser = RouteDowncaser::DowncaseRouteMiddleware.new(app)
+
+Benchmark.bmbm do |bm|
+  # bm.report("Original with small env") do
+  #   ITERATIONS.times do
+  #     env = {
+  #       "PATH_INFO" => "/Here/Or/There",
+  #       "REQUEST_URI" => "/Here/Or/There",
+  #       "REQUEST_METHOD" => "GET",
+  #     }
+  #     original_downcaser.call(env)
+  #   end
+  # end
+  bm.report("Original") do
+    ITERATIONS.times do
+      env = {
+        "PATH_INFO" => "/Here/Or/There",
+        "REQUEST_URI" => "/Here/Or/There",
+        "REQUEST_METHOD" => "GET",
+        "GATEWAY_INTERFACE" => "GATEWAY_INTERFACE",
+        "HTTP_ACCEPT" => "HTTP_ACCEPT",
+        "HTTP_ACCEPT_CHARSET" => "HTTP_ACCEPT_CHARSET",
+        "HTTP_ACCEPT_ENCODING" => "HTTP_ACCEPT_ENCODING",
+        "HTTP_ACCEPT_LANGUAGE" => "HTTP_ACCEPT_LANGUAGE",
+        "HTTP_CACHE_CONTROL" => "HTTP_CACHE_CONTROL",
+        "HTTP_CONNECTION" => "HTTP_CONNECTION",
+        "HTTP_COOKIE" => "HTTP_COOKIE",
+        "HTTP_HOST" => "HTTP_HOST",
+        "HTTP_KEEP_ALIVE" => "HTTP_KEEP_ALIVE",
+        "HTTP_REFERER" => "HTTP_REFERER",
+        "HTTP_USER_AGENT" => "HTTP_USER_AGENT",
+        "QUERY_STRING" => "QUERY_STRING",
+        "REMOTE_ADDR" => "REMOTE_ADDR",
+        "REMOTE_HOST" => "REMOTE_HOST",
+        "REMOTE_USER" => "REMOTE_USER",
+        "SERVER_NAME" => "SERVER_NAME",
+        "SERVER_PORT" => "SERVER_PORT",
+        "SERVER_PROTOCOL" => "SERVER_PROTOCOL",
+        "SERVER_SOFTWARE" => "SERVER_SOFTWARE"
+      }
+      original_downcaser.call(env)
+    end
+  end
+  # bm.report("Optimized with small env") do
+  #   ITERATIONS.times do
+  #     env = {
+  #       "PATH_INFO" => "/Here/Or/There",
+  #       "REQUEST_URI" => "/Here/Or/There",
+  #       "REQUEST_METHOD" => "GET",
+  #     }
+  #     optimized_downcaser.call(env)
+  #   end
+  # end
+  bm.report("Optimized") do
+    ITERATIONS.times do
+      env = {
+        "PATH_INFO" => "/Here/Or/There",
+        "REQUEST_URI" => "/Here/Or/There",
+        "REQUEST_METHOD" => "GET",
+        "GATEWAY_INTERFACE" => "GATEWAY_INTERFACE",
+        "HTTP_ACCEPT" => "HTTP_ACCEPT",
+        "HTTP_ACCEPT_CHARSET" => "HTTP_ACCEPT_CHARSET",
+        "HTTP_ACCEPT_ENCODING" => "HTTP_ACCEPT_ENCODING",
+        "HTTP_ACCEPT_LANGUAGE" => "HTTP_ACCEPT_LANGUAGE",
+        "HTTP_CACHE_CONTROL" => "HTTP_CACHE_CONTROL",
+        "HTTP_CONNECTION" => "HTTP_CONNECTION",
+        "HTTP_COOKIE" => "HTTP_COOKIE",
+        "HTTP_HOST" => "HTTP_HOST",
+        "HTTP_KEEP_ALIVE" => "HTTP_KEEP_ALIVE",
+        "HTTP_REFERER" => "HTTP_REFERER",
+        "HTTP_USER_AGENT" => "HTTP_USER_AGENT",
+        "QUERY_STRING" => "QUERY_STRING",
+        "REMOTE_ADDR" => "REMOTE_ADDR",
+        "REMOTE_HOST" => "REMOTE_HOST",
+        "REMOTE_USER" => "REMOTE_USER",
+        "SERVER_NAME" => "SERVER_NAME",
+        "SERVER_PORT" => "SERVER_PORT",
+        "SERVER_PROTOCOL" => "SERVER_PROTOCOL",
+        "SERVER_SOFTWARE" => "SERVER_SOFTWARE"
+      }
+      optimized_downcaser.call(env)
+    end
+  end
+end