can't shift those any more, config returns a frozen array

lib/postal/fast_server/client.rb

@@ -138,9 +138,8 @@ module Postal
           end
 
           if ssl_context.cert.nil?
-            certs = Postal.smtp_certificates
+            ssl_context.cert = Postal.smtp_certificates[0]
-            ssl_context.cert = certs.shift
+            ssl_context.extra_chain_cert = Postal.smtp_certificates[1..-1]
-            ssl_context.extra_chain_cert = certs
             ssl_context.key  = Postal.smtp_private_key
           end
 

lib/postal/smtp_server/server.rb

@@ -37,9 +37,8 @@ module Postal
       def ssl_context
         @ssl_context ||= begin
           ssl_context      = OpenSSL::SSL::SSLContext.new
-          certs            =  Postal.smtp_certificates
+          ssl_context.cert = Postal.smtp_certificates[0]
-          ssl_context.cert = certs.shift
+          ssl_context.extra_chain_cert = Postal.smtp_certificates[1..-1]
-          ssl_context.extra_chain_cert = certs
           ssl_context.key  = Postal.smtp_private_key
           ssl_context.ssl_version = "SSLv23"
           ssl_context