[cygnusX88]

I'm developing email client and here's my problem...When i connect to the mail account and download all headers and then close the application obviously i want next time when i start the application to populate already downloaded headers and download only these headers which are not downloaded before.I can do that but the problem is i don't know how to associate number to every of the downloaded headers,i mean the number needed for downloading the corresponding letter with the RETR command.I mean when i connect to the account,if i delete few letters then the numbers of all letters in that account are changed.Right?Sorry if i'm wrong but i think that's how the pop3 protocol works.Actually i'm not sure whether this is problem of the pop3 protocol or is problem of the mail account(s).Sorry for my bad english too.Can someone help me with that?