diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e7df177..882c654 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '2.7'
+          ruby-version: '2.6'
           bundler-cache: true
       - name: Run test
         run: bundle exec rubocop
@@ -23,7 +23,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ ruby-head, '3.0', '2.7' ]
+        ruby: [ ruby-head, '3.0', '2.7', '2.6' ]
     steps:
       - name: Checkout
         uses: actions/checkout@v2
diff --git a/.rubocop.yml b/.rubocop.yml
index ed8cfe0..fea2f84 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -2,4 +2,4 @@ inherit_gem:
   rubocop-shopify: rubocop.yml
 
 AllCops:
-  TargetRubyVersion: 2.7
+  TargetRubyVersion: 2.6
diff --git a/Gemfile b/Gemfile
index 2cae264..bf2dd7c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,8 +8,8 @@ gemspec
 gem "msgpack", github: "msgpack/msgpack-ruby"
 
 gem "rake", "~> 13.0"
-gem "activesupport", ">= 7.0.0"
-gem "activerecord", ">= 7.0.0"
+gem "activesupport"
+gem "activerecord"
 gem "sqlite3"
 gem "benchmark-ips"
 
diff --git a/Gemfile.lock b/Gemfile.lock
index a0d7ac2..a935023 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -13,16 +13,17 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    activemodel (7.0.2.3)
-      activesupport (= 7.0.2.3)
-    activerecord (7.0.2.3)
-      activemodel (= 7.0.2.3)
-      activesupport (= 7.0.2.3)
-    activesupport (7.0.2.3)
+    activemodel (6.1.5)
+      activesupport (= 6.1.5)
+    activerecord (6.1.5)
+      activemodel (= 6.1.5)
+      activesupport (= 6.1.5)
+    activesupport (6.1.5)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
       tzinfo (~> 2.0)
+      zeitwerk (~> 2.3)
     ast (2.4.2)
     benchmark-ips (2.10.0)
     byebug (11.1.3)
@@ -56,6 +57,7 @@ GEM
     tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
     unicode-display_width (2.1.0)
+    zeitwerk (2.5.4)
 
 PLATFORMS
   ruby
@@ -63,8 +65,8 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
-  activerecord (>= 7.0.0)
-  activesupport (>= 7.0.0)
+  activerecord
+  activesupport
   benchmark-ips
   byebug
   minitest (~> 5.0)
diff --git a/dev.yml b/dev.yml
index 3c67c4e..686fad9 100644
--- a/dev.yml
+++ b/dev.yml
@@ -2,7 +2,7 @@ name: paquito
 
 up:
   - ruby:
-      version: 2.7.4
+      version: 2.6.9
   - bundler
 
 commands:
diff --git a/lib/paquito/safe_yaml.rb b/lib/paquito/safe_yaml.rb
index decd0a4..2d40e76 100644
--- a/lib/paquito/safe_yaml.rb
+++ b/lib/paquito/safe_yaml.rb
@@ -53,7 +53,7 @@ def [](klass)
         end
       end
 
-      def initialize(...)
+      def initialize(*)
         super
         @permitted_classes = Set.new(@options[:permitted_classes])
         @dispatch_cache = DispatchCache.new(self, @dispatch_cache)
@@ -65,6 +65,7 @@ def initialize(...)
           h[klass] = true
         end.compare_by_identity
       end
+      ruby2_keywords :initialize if respond_to?(:ruby2_keywords, true)
 
       def dump_coder(target)
         return unless permitted_class?(target.class)
diff --git a/paquito.gemspec b/paquito.gemspec
index 20c4d91..d2080c6 100644
--- a/paquito.gemspec
+++ b/paquito.gemspec
@@ -12,7 +12,7 @@ Gem::Specification.new do |spec|
   spec.description   = "Framework for defining efficient and extendable serializers"
   spec.homepage      = "https://github.com/Shopify/paquito"
   spec.license       = "MIT"
-  spec.required_ruby_version = ">= 2.7.0"
+  spec.required_ruby_version = ">= 2.6.0"
 
   spec.metadata["allowed_push_host"] = "https://rubygems.org"