Unable to load the plugin type: Microsoft.Crm.ObjectModel.GlobalActiveStagePlugin

Hi All,

Microsoft has upgraded one of our online training environments to CRM 2013. From then our integrations with another system stopped working. We are getting the following exception in the logs.

Unable to load the plugin type: Microsoft.Crm.ObjectModel.GlobalActiveStagePlugin

I could not find this plugin assembly in our Plugin Registration Tool also.