Since the new update, all mails will be deleted 30 days after receiving them.
My question is, will COD mails also be deleted after 30 days? If so, recipients could basically delete all items you send them via COD at will by leaving the mail unopened and waiting 30 days, which certainly does not seem like it would be intended.
And before anyone says COD mails will be returned after 3 days: That is only the case if the mail is opened, if it stays unopened, it will be returned after 30 days (or atleast that was the case in previous patches I believe), which begs the question if it will be destroyed.