For my internship, I am currently working on a web feed sending the application to ASP.Net (C #). This application registers the open newsletter newsletter.
I use the one-on-one transparent image method described in the following article: http://www.pinpointe.com/blog/how-email-open-and-click-tracking-works to register open speed.
The application can record the number of openings and the date / time when the email was opened. The only thing that is missing is the client (program) with which the email address was opened. This information can help the project team correctly encode the HTML for the newsletter, which is read in the most common email clients.
To track the client from whom the email address is open, I currently use a user agent requesting one image on one of our forms. This information is stored in our database as shown below:
Entries 12 and 13 in this example contain the Microsoft Office Protocol Discovery user agent. This user agent was registered when opening the newsletter in Microsoft Outlook.
? . "Microsoft Outlook 2007" .