If you need to use the uid instead of msgno use
imap_clearflag_full($stream, implode(',', $flags), '\\DELETED', ST_UID);
(PHP 4, PHP 5, PHP 7, PHP 8)
imap_undelete — Unmark the message which is marked deleted
$imap
, string $message_num
, int $flags = 0
) : boolRemoves the deletion flag for a specified message, which is set by imap_delete() or imap_mail_move().
成功时返回 true， 或者在失败时返回 false。
If you need to use the uid instead of msgno use
imap_clearflag_full($stream, implode(',', $flags), '\\DELETED', ST_UID);
The imap_delete function allows the option to use a UID for the message number but the imap_undelete function does not.