No read receipts for Mac Mail on 10.9

[GoogleCodeExporter]

What steps will reproduce the problem?
-->Since the Update to OS X 10.9 the "Request read receipts to" function does 
not work.

What is the expected output? What do you see instead?


What version of the product are you using? On what operating system?
-->Mac OS X 10.9.2; Secrets for Mac Version 1.0.6

Please provide any additional information below.

Original issue reported on code.google.com by [email protected] on 7 May 2014 at 6:43