diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b3742c6..36f13f5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,7 +20,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-20.04 # 22.04 (latest) has build issues
+    runs-on: ubuntu-latest
     timeout-minutes: 10
 
     env:
@@ -53,7 +53,7 @@ jobs:
   build-next:
     if: ${{ always() }}
     needs: build
-    runs-on: ubuntu-20.04 # 22.04 (latest) has build issues
+    runs-on: ubuntu-latest
     timeout-minutes: 10
 
     env:
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 68d6405..7b29724 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -6,7 +6,7 @@ on:
 
 jobs:
   publish:
-    runs-on: ubuntu-20.04 # 22.04 (latest) has build issues
+    runs-on: ubuntu-latest
     timeout-minutes: 10
 
     steps:
diff --git a/mailosaur.gemspec b/mailosaur.gemspec
index 6101e6b..d017a59 100644
--- a/mailosaur.gemspec
+++ b/mailosaur.gemspec
@@ -24,7 +24,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'faraday', '>= 2.0', '< 3'
   s.add_dependency 'json', '>= 1.7.5', '< 4'
 
-  s.add_development_dependency 'mail', '~> 2.7', '>= 2.7.1'
+  s.add_development_dependency 'mail', '~> 2.8'
   s.add_development_dependency 'rake', '~> 13.0'
   s.add_development_dependency 'rubocop', '~> 1.30.0'
   s.add_development_dependency 'shoulda-context', '~> 2.0', '>= 2.0.0'
diff --git a/test/mailer.rb b/test/mailer.rb
index 704e762..ce8de92 100644
--- a/test/mailer.rb
+++ b/test/mailer.rb
@@ -1,48 +1,47 @@
 require 'mail'
 
 Mail.defaults do
-    delivery_method :smtp, {
-      address: ENV['MAILOSAUR_SMTP_HOST'] || 'mailosaur.net',
-      port: ENV['MAILOSAUR_SMTP_PORT'] || 25,
-      enable_starttls_auto: false
-    }
+  delivery_method :smtp, {
+    address: ENV['MAILOSAUR_SMTP_HOST'] || 'mailosaur.net',
+    port: ENV['MAILOSAUR_SMTP_PORT'] || 25
+  }
 end
 
 class Mailer
-    @@html = File.open('test/resources/testEmail.html').read
-    @@text = File.open('test/resources/testEmail.txt').read
-    @@verified_domain = ENV['MAILOSAUR_VERIFIED_DOMAIN'] || 'mailosaur.net'
-
-    def self.send_emails(client, server, quantity)
-        (1..quantity).each do |_i|
-            send_email(client, server)
-        end
+  @@html = File.open('test/resources/testEmail.html').read
+  @@text = File.open('test/resources/testEmail.txt').read
+  @@verified_domain = ENV['MAILOSAUR_VERIFIED_DOMAIN'] || 'mailosaur.net'
+
+  def self.send_emails(client, server, quantity)
+    (1..quantity).each do |_i|
+      send_email(client, server)
     end
+  end
 
-    def self.send_email(client, server, send_to_address = nil)
-        Mail.deliver do
-            random_string = (0...10).map { rand(65..90).chr }.join
+  def self.send_email(client, server, send_to_address = nil)
+    Mail.deliver do
+      random_string = (0...10).map { rand(65..90).chr }.join
 
-            subject '%s subject' % [random_string]
-            random_to_address = send_to_address || client.servers.generate_email_address(server)
+      subject format('%s subject', random_string)
+      random_to_address = send_to_address || client.servers.generate_email_address(server)
 
-            from '%s %s <%s@%s>' % [random_string, random_string, random_string, @@verified_domain]
-            to '%s %s <%s>' % [random_string, random_string, random_to_address]
+      from format('%s %s <%s@%s>', random_string, random_string, random_string, @@verified_domain)
+      to format('%s %s <%s>', random_string, random_string, random_to_address)
 
-            text_part do
-                body @@text.to_s.gsub('REPLACED_DURING_TEST', random_string)
-            end
+      text_part do
+        body @@text.to_s.gsub('REPLACED_DURING_TEST', random_string)
+      end
 
-            html_part do
-                content_type 'text/html; charset=UTF-8'
-                body @@html.to_s.gsub('REPLACED_DURING_TEST', random_string)
-            end
+      html_part do
+        content_type 'text/html; charset=UTF-8'
+        body @@html.to_s.gsub('REPLACED_DURING_TEST', random_string)
+      end
 
-            add_file 'test/resources/cat.png'
-            add_file 'test/resources/dog.png'
+      add_file 'test/resources/cat.png'
+      add_file 'test/resources/dog.png'
 
-            inline = attachments['cat.png']
-            inline.content_id = 'ii_1435fadb31d523f6'
-        end
+      inline = attachments['cat.png']
+      inline.content_id = 'ii_1435fadb31d523f6'
     end
+  end
 end