diff --git a/Appraisals b/Appraisals
index 35da0648..337b50b6 100644
--- a/Appraisals
+++ b/Appraisals
@@ -3,12 +3,12 @@ appraise "rails-4" do
   gem 'bigdecimal', '~> 1.4'
 end
 
-appraise "rails-5" do
-  gem 'activemodel', '~> 5.0.7'
-  gem 'bigdecimal'
-end
+# appraise "rails-5" do
+#   gem 'activemodel', '~> 5.0.7'
+#   gem 'bigdecimal'
+# end
 
-appraise "rails-6" do
-  gem 'activemodel', '~> 6.0.1'
-  gem 'bigdecimal'
-end
+# appraise "rails-6" do
+#   gem 'activemodel', '~> 6.0.1'
+#   gem 'bigdecimal'
+# end
diff --git a/Dockerfile b/Dockerfile
index 50fac1b7..25c9d852 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,12 +1,15 @@
-ARG RUBY_VERSION=${RUBY_VERSION:-3.2.0}
+ARG RUBY_VERSION=${RUBY_VERSION:-2.7}
 FROM ruby:${RUBY_VERSION}-alpine
 
 RUN apk --update add --no-cache build-base bash && \
   apk add git && \
-  apk add --no-cache libffi-dev && \
   apk add --no-cache libxml2 && \
   apk add --no-cache libxml2-dev && \
-  apk add --no-cache sqlite-dev
+  apk add --no-cache sqlite-dev && \
+  apk add --no-cache musl-dev && \
+  apk add --no-cache libc6-compat
+
+RUN gem install nokogiri -v '1.15.6' -- --use-system-libraries
 
 RUN gem update --system 3.3.22 --no-document && \
   gem install bundler --no-document
diff --git a/spec/factories/accounts.rb b/spec/factories/accounts.rb
index 27b01df3..dc5149d8 100644
--- a/spec/factories/accounts.rb
+++ b/spec/factories/accounts.rb
@@ -1,4 +1,4 @@
-FactoryGirl.define do
+FactoryBot.define do
   factory :account, :class => Zuora::Objects::Account do
     sequence(:name){|n| "Test Account #{n}"}
     sequence(:account_number){|n| "test_account_#{n}" }
@@ -6,7 +6,7 @@
 
   factory :active_account, :parent => :account do
     after_create do |account|
-      contact = FactoryGirl.create(:contact, :account => account, :country => "GB")
+      contact = FactoryBot.create(:contact, :account => account, :country => "GB")
       account.bill_to = contact
       account.sold_to = contact
       account.status = "Active"
diff --git a/spec/factories/contacts.rb b/spec/factories/contacts.rb
index daab9721..e6cc5524 100644
--- a/spec/factories/contacts.rb
+++ b/spec/factories/contacts.rb
@@ -1,6 +1,6 @@
-FactoryGirl.define do
+FactoryBot.define do
   factory :contact, :class => Zuora::Objects::Contact do
-    first_name "Example"
+    first_name { "Example" }
     sequence(:last_name){|n| "User #{n}" }
   end
 end
diff --git a/spec/factories/payment_methods.rb b/spec/factories/payment_methods.rb
index 50723ff2..9d3e1309 100644
--- a/spec/factories/payment_methods.rb
+++ b/spec/factories/payment_methods.rb
@@ -1,34 +1,36 @@
-FactoryGirl.define do
+FactoryBot.define do
   factory :payment_method_credit_card, :class => Zuora::Objects::PaymentMethod do
-    type "CreditCard"
-    credit_card_address1 "123 Testing Lane"
-    credit_card_city "San Francisco"
-    credit_card_state "California"
-    credit_card_postal_code "95611"
-    credit_card_holder_name "Example User"
-    credit_card_number "4111111111111111"
-    credit_card_type "Visa"
-    credit_card_expiration_month "9"
-    credit_card_expiration_year "2018"
+    type { "CreditCard" }
+    credit_card_address1 { "123 Testing Lane" }
+    credit_card_city { "San Francisco" }
+    credit_card_state { "California" }
+    credit_card_postal_code { "95611" }
+    credit_card_holder_name { "Example User" }
+    credit_card_number { "4111111111111111" }
+    credit_card_type { "Visa" }
+    credit_card_expiration_month { "9" }
+    credit_card_expiration_year { "2018" }
   end
 
   factory :payment_method_debit_card, :parent => :payment_method_credit_card do
-    type "DebitCard"
+    type { "DebitCard" }
   end
 
-  factory :payment_method_ach, :class => Zuora::Objects::PaymentMethod do
-    type "ACH"
-    ach_aba_code '123456789'
-    ach_account_name 'My Checking Account'
-    ach_account_number '987654321'
-    ach_bank_name 'Bank of Zuora'
-    ach_account_type 'BusinessChecking'
-  end
+  FactoryBot.define do
+    factory :payment_method_ach, class: Zuora::Objects::PaymentMethod do
+      type { "ACH" }
+      ach_aba_code { '123456789' }
+      ach_account_name { 'My Checking Account' }
+      ach_account_number { '987654321' }
+      ach_bank_name { 'Bank of Zuora' }
+      ach_account_type { 'BusinessChecking' }
+    end
 
-  factory :payment_method_paypal, :class => Zuora::Objects::PaymentMethod do
-    type 'PayPal'
-    paypal_baid "ExampleBillingAgreementId"
-    paypal_email "example@example.org"
-    paypal_type "ExpressCheckout"
+    factory :payment_method_paypal, class: Zuora::Objects::PaymentMethod do
+      type { 'PayPal' }
+      paypal_baid { "ExampleBillingAgreementId" }
+      paypal_email { "example@example.org" }
+      paypal_type { "ExpressCheckout" }
+    end
   end
 end
diff --git a/spec/factories/product_rate_plan_charge_tiers.rb b/spec/factories/product_rate_plan_charge_tiers.rb
index d796f749..d7e688a3 100644
--- a/spec/factories/product_rate_plan_charge_tiers.rb
+++ b/spec/factories/product_rate_plan_charge_tiers.rb
@@ -1,7 +1,7 @@
-FactoryGirl.define do
+FactoryBot.define do
   factory :product_rate_plan_charge_tier, :class => Zuora::Objects::ProductRatePlanChargeTier do
-    price 0
-    starting_unit 0
-    ending_unit 10
+    price { 0 }
+    starting_unit { 0 }
+    ending_unit { 10 }
   end
 end
diff --git a/spec/factories/product_rate_plan_charges.rb b/spec/factories/product_rate_plan_charges.rb
index 64fe8297..49ffa0e7 100644
--- a/spec/factories/product_rate_plan_charges.rb
+++ b/spec/factories/product_rate_plan_charges.rb
@@ -1,18 +1,18 @@
-FactoryGirl.define do
-  factory :product_rate_plan_charge, :class => Zuora::Objects::ProductRatePlanCharge do
+FactoryBot.define do
+  factory :product_rate_plan_charge, class: Zuora::Objects::ProductRatePlanCharge do
     association :product_rate_plan
     sequence(:name){|n| "Rate Plan Charge #{n}"}
-    bill_cycle_type "DefaultFromCustomer"
-    billing_period "Month"
-    billing_period_alignment "AlignToCharge"
-    charge_model "Volume Pricing"
-    charge_type "Recurring"
-    included_units "1"
-    smoothing_model "Rollover"
-    uom "Each"
-    trigger_event "ServiceActivation"
-    after_build do |prpc|
-      prpc.product_rate_plan_charge_tiers << FactoryGirl.build(:product_rate_plan_charge_tier)
+    bill_cycle_type { "DefaultFromCustomer" }
+    billing_period { "Month" }
+    billing_period_alignment { "AlignToCharge" }
+    charge_model { "Volume Pricing" }
+    charge_type { "Recurring" }
+    included_units { "1" }
+    smoothing_model { "Rollover" }
+    uom { "Each" }
+    trigger_event { "ServiceActivation" }
+    after(:build) do |prpc|
+      prpc.product_rate_plan_charge_tiers << FactoryBot.build(:product_rate_plan_charge_tier)
     end
   end
 end
diff --git a/spec/factories/product_rate_plans.rb b/spec/factories/product_rate_plans.rb
index c2d902b4..4cc53a22 100644
--- a/spec/factories/product_rate_plans.rb
+++ b/spec/factories/product_rate_plans.rb
@@ -1,8 +1,8 @@
-FactoryGirl.define do
-  factory :product_rate_plan, :class => Zuora::Objects::ProductRatePlan do
+FactoryBot.define do
+  factory :product_rate_plan, class: Zuora::Objects::ProductRatePlan do
     sequence(:name){|n| "Rate Plan #{n}"}
     association :product
-    effective_start_date DateTime.now
-    effective_end_date   DateTime.now + 10.days
+    effective_start_date { DateTime.now }
+    effective_end_date   { DateTime.now + 10.days }
   end
 end
diff --git a/spec/factories/products.rb b/spec/factories/products.rb
index 7a53dd2c..9422a2e9 100644
--- a/spec/factories/products.rb
+++ b/spec/factories/products.rb
@@ -1,14 +1,14 @@
-FactoryGirl.define do
-  factory :product, :class => Zuora::Objects::Product do
-    sequence(:name){|n| "Example Product #{n}"}
-    effective_start_date DateTime.now
-    effective_end_date   DateTime.now + 10.days
+FactoryBot.define do
+  factory :product, class: Zuora::Objects::Product do
+    sequence(:name) { |n| "Example Product #{n}" }
+    effective_start_date { DateTime.now }
+    effective_end_date { DateTime.now + 10.days }
   end
 
-  factory :product_catalog, :parent => :product do
-    after_create do |product|
-      rate_plan = FactoryGirl.create(:product_rate_plan, :product => product)    
-      FactoryGirl.create(:product_rate_plan_charge, :product_rate_plan => rate_plan)
+  factory :product_catalog, parent: :product do
+    after(:create) do |product|
+      rate_plan = FactoryBot.create(:product_rate_plan, product: product)
+      FactoryBot.create(:product_rate_plan_charge, product_rate_plan: rate_plan)
     end
   end
 end
diff --git a/spec/factories/subscriptions.rb b/spec/factories/subscriptions.rb
index 544dbac0..13601b0c 100644
--- a/spec/factories/subscriptions.rb
+++ b/spec/factories/subscriptions.rb
@@ -1,7 +1,7 @@
-FactoryGirl.define do
-  factory :subscription, :class => Zuora::Objects::Subscription do
-    contract_effective_date DateTime.now
-    sequence(:name){|n| "Example Subscription #{n}"}
-    term_start_date DateTime.now
+FactoryBot.define do
+  factory :subscription, class: Zuora::Objects::Subscription do
+    contract_effective_date { DateTime.now }
+    sequence(:name) { |n| "Example Subscription #{n}" }
+    term_start_date { DateTime.now }
   end
 end
diff --git a/spec/integration/account_management_spec.rb b/spec/integration/account_management_spec.rb
index aeb7af02..7df427ae 100644
--- a/spec/integration/account_management_spec.rb
+++ b/spec/integration/account_management_spec.rb
@@ -6,7 +6,7 @@
 
     before :each do
       authenticate!
-      @account = FactoryGirl.create(:account, :account_number => generate_key)
+      @account = FactoryBot.create(:account, :account_number => generate_key)
     end
 
     after :each do
@@ -15,7 +15,7 @@
 
     describe "adding and manipulating contacts" do
       it "is supported" do
-        contact = FactoryGirl.create(:contact, :account => @account, :country => "GB")
+        contact = FactoryBot.create(:contact, :account => @account, :country => "GB")
         @account.bill_to = contact
         @account.sold_to = contact
         @account.save.should == true
@@ -27,23 +27,23 @@
 
     describe "supported payment methods" do
       it "includes credit cards" do
-        FactoryGirl.create(:payment_method_credit_card, :account => @account)
+        FactoryBot.create(:payment_method_credit_card, :account => @account)
       end
 
       it "includes ACH" do
-        FactoryGirl.create(:payment_method_ach, :account => @account)
+        FactoryBot.create(:payment_method_ach, :account => @account)
       end
 
       it "includes PayPal" do
         # TODO: This cannot work unless Zuora is set up with proper paypal configs.
-        # FactoryGirl.create(:payment_method_paypal, :account => @account)
+        # FactoryBot.create(:payment_method_paypal, :account => @account)
       end
     end
   end
 
   describe "an active account fixture" do
     it "can be destroyed" do
-      account = FactoryGirl.create(:active_account, :account_number => generate_key)
+      account = FactoryBot.create(:active_account, :account_number => generate_key)
       account.status.should == 'Active'
       account.destroy.should == true
     end
diff --git a/spec/integration/product_catalog_spec.rb b/spec/integration/product_catalog_spec.rb
index b654ed96..e56232c7 100644
--- a/spec/integration/product_catalog_spec.rb
+++ b/spec/integration/product_catalog_spec.rb
@@ -9,8 +9,8 @@
   after do
     Zuora::Objects::Product.where(:name => @product_name).map(&:destroy)
   end
-  
+
   it "creates a product catalog" do
-    product_catalog = FactoryGirl.create(:product_catalog, :name => @product_name)
+    product_catalog = FactoryBot.create(:product_catalog, :name => @product_name)
   end
 end
diff --git a/spec/integration/subscription_spec.rb b/spec/integration/subscription_spec.rb
index b95d6aa8..8528715f 100644
--- a/spec/integration/subscription_spec.rb
+++ b/spec/integration/subscription_spec.rb
@@ -3,8 +3,8 @@
 describe 'Subscription', type: :integration do
   before :each do
     authenticate!
-    @account = FactoryGirl.create(:active_account, account_number: generate_key)
-    @product = FactoryGirl.create(:product_catalog, name: generate_key)
+    @account = FactoryBot.create(:active_account, account_number: generate_key)
+    @product = FactoryBot.create(:product_catalog, name: generate_key)
   end
 
   after :each do
@@ -13,10 +13,10 @@
   end
 
   it 'can be created' do
-    payment_method = FactoryGirl.create(:payment_method_credit_card, account: @account)
+    payment_method = FactoryBot.create(:payment_method_credit_card, account: @account)
     bill_to_contact = @account.contacts.first
     product_rate_plan = @product.product_rate_plans.first
-    subscription = FactoryGirl.build(:subscription, account: @account)
+    subscription = FactoryBot.build(:subscription, account: @account)
 
     request = Zuora::Objects::SubscribeRequest.new(
       account: @account,
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 86098384..cfdd8623 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -6,7 +6,7 @@
 require 'zuora'
 require 'artifice'
 require 'digest/md5'
-require 'factory_girl'
+require 'factory_bot'
 
 Dir["#{File.dirname(__FILE__)}/../spec/support/**/*.rb"].sort.each { |ext| require ext }
 Dir["#{File.dirname(__FILE__)}/../spec/factories/*.rb"].sort.each { |ext| require ext }
diff --git a/spec/zuora/objects/payment_method_spec.rb b/spec/zuora/objects/payment_method_spec.rb
index dbfa9995..c01e496e 100644
--- a/spec/zuora/objects/payment_method_spec.rb
+++ b/spec/zuora/objects/payment_method_spec.rb
@@ -9,29 +9,29 @@
 
   context 'Type helpers' do
     it 'supports credit_card?' do
-      FactoryGirl.build(:payment_method_credit_card).should be_credit_card
+      FactoryBot.build(:payment_method_credit_card).should be_credit_card
     end
 
     it 'supports ach?' do
-      FactoryGirl.build(:payment_method_ach).should be_ach
+      FactoryBot.build(:payment_method_ach).should be_ach
     end
 
     it 'supports paypal?' do
-      FactoryGirl.build(:payment_method_paypal).should be_paypal
+      FactoryBot.build(:payment_method_paypal).should be_paypal
     end
 
     it 'supports debit_card?' do
-      FactoryGirl.build(:payment_method_debit_card).should be_debit_card
+      FactoryBot.build(:payment_method_debit_card).should be_debit_card
     end
 
     it 'supports card?' do
-      FactoryGirl.build(:payment_method_credit_card).should be_card
-      FactoryGirl.build(:payment_method_debit_card).should be_card
+      FactoryBot.build(:payment_method_credit_card).should be_card
+      FactoryBot.build(:payment_method_debit_card).should be_card
     end
   end
 
   context 'write only attributes' do
-    ach = FactoryGirl.build(:payment_method_ach)
+    ach = FactoryBot.build(:payment_method_ach)
     ach.write_only_attributes.should == [:ach_account_number, :credit_card_number,
       :credit_card_security_code, :gateway_option_data, :skip_validation, :bank_transfer_account_number]
   end
@@ -62,7 +62,7 @@
   describe "Credit Card" do
     it "generates proper request xml" do
       MockResponse.responds_with(:payment_method_credit_card_create_success) do
-        FactoryGirl.create(:payment_method_credit_card, :account => @account, credit_card_expiration_year: '2025')
+        FactoryBot.create(:payment_method_credit_card, :account => @account, credit_card_expiration_year: '2025')
 
         xml = Zuora::Api.instance.last_request
         xml.should have_xml("//env:Body/#{zns}:create/#{zns}:zObjects/#{ons}:Type").
@@ -99,7 +99,7 @@
   context 'ACH' do
     it 'generates proper request xml' do
       MockResponse.responds_with(:payment_method_ach_create_success) do
-        FactoryGirl.create(:payment_method_ach, account: @account)
+        FactoryBot.create(:payment_method_ach, account: @account)
 
         xml = Zuora::Api.instance.last_request
         xml.should have_xml("//env:Body/#{zns}:create/#{zns}:zObjects/#{ons}:Type")
@@ -128,7 +128,7 @@
   context 'PayPal' do
     it 'generates proper request xml' do
       MockResponse.responds_with(:payment_method_ach_create_success) do
-        FactoryGirl.create(:payment_method_paypal, account: @account)
+        FactoryBot.create(:payment_method_paypal, account: @account)
 
         xml = Zuora::Api.instance.last_request
         xml.should have_xml("//env:Body/#{zns}:create/#{zns}:zObjects/#{ons}:Type")
diff --git a/spec/zuora/objects/subscribe_request_spec.rb b/spec/zuora/objects/subscribe_request_spec.rb
index f79778c8..10b8ef48 100644
--- a/spec/zuora/objects/subscribe_request_spec.rb
+++ b/spec/zuora/objects/subscribe_request_spec.rb
@@ -28,7 +28,7 @@
         subject.product_rate_plan = Zuora::Objects::ProductRatePlan.find('stub')
       end
 
-      subject.subscription = FactoryGirl.build(:subscription)
+      subject.subscription = FactoryBot.build(:subscription)
     end
 
     it "provides properly formatted xml when using existing objects" do
@@ -52,7 +52,7 @@
     end
 
     it "provides full account info when new object" do
-      subject.account = FactoryGirl.build(:account)
+      subject.account = FactoryBot.build(:account)
 
       MockResponse.responds_with(:subscribe_request_success) do
         subject.should be_valid
@@ -68,7 +68,7 @@
     end
 
     it "provides full bill_to_contact info when new object" do
-      subject.bill_to_contact = FactoryGirl.build(:contact, :account => @account)
+      subject.bill_to_contact = FactoryBot.build(:contact, :account => @account)
 
       MockResponse.responds_with(:subscribe_request_success) do
         subject.should be_valid
@@ -83,7 +83,7 @@
     end
 
     it "provides full payment_method info when new object" do
-      subject.payment_method = FactoryGirl.build(:payment_method_ach, :account => @account, :ach_account_name => 'Testing')
+      subject.payment_method = FactoryBot.build(:payment_method_ach, :account => @account, :ach_account_name => 'Testing')
 
       MockResponse.responds_with(:subscribe_request_success) do
         subject.should be_valid
diff --git a/zuora.gemspec b/zuora.gemspec
index 1bab295c..ebf4268e 100644
--- a/zuora.gemspec
+++ b/zuora.gemspec
@@ -21,8 +21,8 @@ Gem::Specification.new do |s|
   s.extra_rdoc_files = ['README.md']
 
   s.add_dependency 'activemodel', '>= 4.2.11'
-  s.add_dependency 'activesupport', '>= 4.2.11'
-  s.add_dependency 'httpi', '~> 4.0.2'
+  # s.add_dependency 'activesupport', '>= 4.2.11'
+  # s.add_dependency 'httpi', '~> 4.0.2'
   s.add_dependency 'i18n', '~> 0.7'
   s.add_dependency 'libxml4r', '~> 0.2.6'
   s.add_dependency 'savon', '~> 2.15.0'
@@ -37,7 +37,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'redcarpet', '~> 2.1.0'
   s.add_development_dependency 'rspec', '~> 3.0'
   s.add_development_dependency 'simplecov', '~> 0.22.0'
-  s.add_development_dependency 'sqlite3', '~> 2.0'
+  s.add_development_dependency 'sqlite3', '~> 1.3'
   s.add_development_dependency 'test-unit'
   s.add_development_dependency 'yard', '~> 0.7.5'
 end