Why an android device overwrites the header named message-ID? I do not understand why android devices (I think mobiles devices in general) overwrite the mail header named message-ID. I need to pass some parameters through this header to build threads but each time I try, is overwritten. 
My apps works very well with webmail and mail clients like Outlook and Thunderbird.
Any idea? Do you know some apps to debug mail headers within android devices?
Thanks
Adam
There are mail headers for threading (in particular I'm thinking of References: and In-Reply-To:), why not use one of those rather than trying to overload something else?