The imap_delete function allows the option to use a UID for the message number but the imap_undelete function does not.
(PHP 4, PHP 5, PHP 7)
imap_undelete — Unmark the message which is marked deleted
$imap_stream
, int $msg_number
[, int $flags
= 0
] ) : boolRemoves the deletion flag for a specified message, which is set by imap_delete() or imap_mail_move().
imap_stream
Um stream IMAP retornado por imap_open().
msg_number
The message number
flags
Retorna true
em caso de sucesso ou false
em caso de falha.
The imap_delete function allows the option to use a UID for the message number but the imap_undelete function does not.