diff --git a/lib/pact/consumer/configuration/mock_service.rb b/lib/pact/consumer/configuration/mock_service.rb
index 0314e92b..bbeb81ab 100644
--- a/lib/pact/consumer/configuration/mock_service.rb
+++ b/lib/pact/consumer/configuration/mock_service.rb
@@ -20,7 +20,7 @@ def initialize name, consumer_name, provider_name
           @port = nil
           @standalone = false
           @verify = true
-          @pact_specification_version = nil
+          @pact_specification_version = '2'
           @finalized = false
         end