We regret the inconvenience caused to you. However, we can not be of much help to you in this regard as we don’t fix issues in older versions. This is as according to our quality policy where we only fix issues that are reproducible with the latest version of the API. Moreover, fixing such issue can lead to other potential problems that would have been, otherwise, dealt in our routine monthly releases. So, its not practical for us to fix an issue with an older version and provide the fixed version. We hope you understand our point of view in this regard.
PS: Upgrading to the latest version of the API do have changes related to restructured namespaces. However, upgrading to this restructure namespace of the API is completely
[documented](https://docs.aspose.com/display/emailnet/Aspose.Email+for+.NET+16.12.0+(Revamped)+Release+Notes) and can be followed to cater for this change in the API namespace structure.