diff --git a/app/mailboxes/application_mailbox.rb b/app/mailboxes/application_mailbox.rb
index f5e9abe1b..9af5aa876 100644
--- a/app/mailboxes/application_mailbox.rb
+++ b/app/mailboxes/application_mailbox.rb
@@ -6,80 +6,41 @@ class ApplicationMailbox < ActionMailbox::Base
   REPLY_EMAIL_UUID_PATTERN = /^reply\+([0-9a-f]{8}\b-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-\b[0-9a-f]{12})$/i
   CONVERSATION_MESSAGE_ID_PATTERN = %r{conversation/([a-zA-Z0-9\-]*?)/messages/(\d+?)@(\w+\.\w+)}
 
-  def self.reply_mail?
-    proc do |inbound_mail_obj|
-      is_a_reply_email = false
-      inbound_mail_obj.mail.to&.each do |email|
-        is_a_reply_email = true if reply_uuid_mail?(email)
-      end
-      is_a_reply_email = true if in_reply_to_mail?(inbound_mail_obj, is_a_reply_email)
-
-      is_a_reply_email
-    end
-  end
-
-  def self.support_mail?
-    proc do |inbound_mail_obj|
-      is_a_support_email = false
-
-      is_a_support_email = true if reply_to_mail?(inbound_mail_obj, is_a_support_email)
-
-      is_a_support_email
-    end
-  end
-
-  def self.reply_to_mail?(inbound_mail_obj, is_a_support_email)
-    return if is_a_support_email
-
-    channel = EmailChannelFinder.new(inbound_mail_obj.mail).perform
-    channel.present?
-  end
-
-  def self.catch_all_mail?
-    proc { |_mail| true }
-  end
-
-  # checks if follow this pattern then send it to reply_mailbox
-  # <account/#{@account.id}/conversation/#{@conversation.uuid}@#{@account.inbound_email_domain}>
-  def self.in_reply_to_mail?(inbound_mail_obj, is_a_reply_email)
-    return if is_a_reply_email
-
-    in_reply_to = inbound_mail_obj.mail.in_reply_to
-
-    return false if in_reply_to.blank?
-
-    return true if in_reply_to_matches?(in_reply_to)
-
-    message = Message.find_by(source_id: in_reply_to)
-    return true if message.present?
-
-    false
-  end
-
-  def self.in_reply_to_matches?(in_reply_to)
-    in_reply_to_match = false
-    if in_reply_to.is_a?(Array)
-      in_reply_to.each do |in_reply_to_mail|
-        in_reply_to_match ||= in_reply_to_mail.match(CONVERSATION_MESSAGE_ID_PATTERN)
-      end
-    else
-      in_reply_to_match = in_reply_to.match(CONVERSATION_MESSAGE_ID_PATTERN)
-    end
-    in_reply_to_match
-  end
-
-  # checks if follow this pattern  send it to reply_mailbox
-  # reply+<conversation-uuid>@<mailer-domain.com>
-  def self.reply_uuid_mail?(email)
-    conversation_uuid = email.split('@')[0]
-    conversation_uuid.match(REPLY_EMAIL_UUID_PATTERN)
-  end
-
-  # routing should be defined below the referenced procs
-
   # routes as a reply to existing conversations
-  routing(reply_mail? => :reply)
+  routing(
+    ->(inbound_mail) { reply_uuid_mail?(inbound_mail) || in_reply_to_mail?(inbound_mail) } => :reply
+  )
+
   # routes as a new conversation in email channel
-  routing(support_mail? => :support)
-  routing(catch_all_mail? => :default)
+  routing(
+    ->(inbound_mail) { EmailChannelFinder.new(inbound_mail.mail).perform.present? } => :support
+  )
+
+  # catchall
+  routing(all: :default)
+
+  class << self
+    # checks if follow this pattern then send it to reply_mailbox
+    # <account/#{@account.id}/conversation/#{@conversation.uuid}@#{@account.inbound_email_domain}>
+    def in_reply_to_mail?(inbound_mail)
+      in_reply_to = inbound_mail.mail.in_reply_to
+
+      in_reply_to.present? && (
+        in_reply_to_matches?(in_reply_to) || Message.exists?(source_id: in_reply_to)
+      )
+    end
+
+    def in_reply_to_matches?(in_reply_to)
+      Array.wrap(in_reply_to).any? { _1.match?(CONVERSATION_MESSAGE_ID_PATTERN) }
+    end
+
+    # checks if follow this pattern  send it to reply_mailbox
+    # reply+<conversation-uuid>@<mailer-domain.com>
+    def reply_uuid_mail?(inbound_mail)
+      inbound_mail.mail.to&.any? do |email|
+        conversation_uuid = email.split('@')[0]
+        conversation_uuid.match?(REPLY_EMAIL_UUID_PATTERN)
+      end
+    end
+  end
 end