diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c1f2c78..07e410e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.3", "2.4", "2.5", "2.6", "2.7", "3.0", "3.1", "3.2", "3.3"]
+        ruby: ["2.3", "2.4", "2.5", "2.6", "2.7", "3.0", "3.1", "3.2", "3.3", "head"]
     steps:
       - run: sudo apt-get install libcurl4-openssl-dev
       - uses: actions/checkout@v4
diff --git a/lib/em-http/client.rb b/lib/em-http/client.rb
index ab25bb9..89cecbd 100644
--- a/lib/em-http/client.rb
+++ b/lib/em-http/client.rb
@@ -1,3 +1,9 @@
+require 'uri'
+
+if !defined?(URI::REGEXP::PATTERN)
+  URI.parser = URI::RFC2396_PARSER
+end
+
 require 'cookiejar'
 
 module EventMachine