diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 605363e..855d92e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,15 +13,13 @@ jobs:
       fail-fast: false
       matrix:
         ruby:
-          - "2.4"
-          - "2.5"
-          - "2.6"
           - "2.7"
           - "3.0"
           - "3.1"
           - "3.2"
           - "3.3"
           - "3.4"
+          - "4.0"
           - "jruby-9.4"
 
     services:
diff --git a/down.gemspec b/down.gemspec
index a2092f3..2b38e8c 100644
--- a/down.gemspec
+++ b/down.gemspec
@@ -4,7 +4,7 @@ Gem::Specification.new do |spec|
   spec.name         = "down"
   spec.version      = Down::VERSION
 
-  spec.required_ruby_version = ">= 2.4"
+  spec.required_ruby_version = ">= 2.7"
 
   spec.summary      = "Robust streaming downloads using Net::HTTP, http.rb or HTTPX."
   spec.homepage     = "https://github.com/janko/down"
@@ -16,12 +16,13 @@ Gem::Specification.new do |spec|
   spec.require_path = "lib"
 
   spec.add_dependency "addressable", "~> 2.8"
+  spec.add_dependency "base64", "~> 0.3"
 
   spec.add_development_dependency "minitest", "~> 5.8"
   spec.add_development_dependency "mocha", "~> 1.5"
   spec.add_development_dependency "rake"
-  spec.add_development_dependency "httpx", RUBY_VERSION >= "2.7" ? "~> 1.0" : "~> 0.24"
-  spec.add_development_dependency "http", RUBY_VERSION >= "2.5" ? "~> 5.0" : "~> 4.3"
+  spec.add_development_dependency "httpx", "~> 1.0", "< 1.4.4"
+  spec.add_development_dependency "http", "~> 5.0"
   spec.add_development_dependency "warning"
   spec.add_development_dependency "csv"
 end
diff --git a/lib/down/net_http.rb b/lib/down/net_http.rb
index 996182a..9e773f8 100644
--- a/lib/down/net_http.rb
+++ b/lib/down/net_http.rb
@@ -93,7 +93,7 @@ def download(url, *args, **options)
         uri.password = nil
       end
 
-      open_uri_file = open_uri(uri, open_uri_options, follows_remaining: max_redirects, auth_on_redirect: )
+      open_uri_file = open_uri(uri, open_uri_options, follows_remaining: max_redirects, auth_on_redirect: auth_on_redirect)
 
       # Handle the fact that open-uri returns StringIOs for small files.
       extname = extension ? ".#{extension}" : File.extname(open_uri_file.base_uri.path)
@@ -117,7 +117,7 @@ def open(url, *args, **options)
 
       # Create a Fiber that halts when response headers are received.
       request = Fiber.new do
-        net_http_request(uri, options, follows_remaining: max_redirects, auth_on_redirect:) do |response|
+        net_http_request(uri, options, follows_remaining: max_redirects, auth_on_redirect: auth_on_redirect) do |response|
           Fiber.yield response
         end
       end
@@ -249,7 +249,7 @@ def net_http_request(uri, options, follows_remaining:, auth_on_redirect:, &block
           uri.password = nil unless auth_on_redirect
         end
 
-        net_http_request(location, options, follows_remaining: follows_remaining - 1, auth_on_redirect:, &block)
+        net_http_request(location, options, follows_remaining: follows_remaining - 1, auth_on_redirect: auth_on_redirect, &block)
       end
     end