diff --git a/app/models/avatax/request_decorator.rb b/app/models/avatax/request_decorator.rb
index 924c8daf..cac7ba50 100644
--- a/app/models/avatax/request_decorator.rb
+++ b/app/models/avatax/request_decorator.rb
@@ -2,10 +2,12 @@ module Avatax
   module RequestDecorator
     include ::SpreeAvataxOfficial::HttpHelper
 
-    def request(method, path, model, options = {})
+    def request(method, path, model, options = {}, apiversion="", headers=Hash.new)
       max_retries                  ||= ::SpreeAvataxOfficial::Config.max_retries
       uri_encoded_path               = URI.parse(path).to_s
       response                       = connection.send(method) do |request|
+        request.headers['X-Avalara-Client'] = request.headers['X-Avalara-Client'].gsub("API_VERSION", apiversion)
+        request.headers=request.headers.merge(headers)  unless headers.empty?
         request.options['timeout'] ||= 1_200
         case method
         when :get, :delete