Steps to reproduce:

1. PHP 8.2.17, Phorge at 216d308507edd54a68cb392df9f47011265c64e9
2. Install php-mailparse if it is not already installed
3. Be too lazy to set up a mail server software
4. Have a local text file called email.txt with a valid mbox email message in it and place it in ./phorge/scripts/mail/
5. In https://we.phorge.it/source/phorge/browse/master/scripts/mail/mail_handler.php , replace the line $parser->setText(file_get_contents('php://stdin')); with $parser->setText(file_get_contents('email.txt'));
6. Run php ./phorge/scripts/mail/mail_handler.php

Expected outcome:
No errors

Actual outcome:

# [2024-03-29 09:43:56] ERROR 8192: Creation of dynamic property MimeMailParser::$parts is deprecated at [/var/www/html/phorge/phorge/externals/mimemailparser/MimeMailParser.class.php:137]
#arcanist(head=master, ref.master=ef73b12b580e), phorge(head=master, ref.master=216d308507ed)
#  #0 MimeMailParser::parse() called at [<phorge>/externals/mimemailparser/MimeMailParser.class.php:126]
#  #1 MimeMailParser::setText(string) called at [<phorge>/scripts/mail/mail_handler.php:37]

because https://php.watch/versions/8.2/dynamic-properties-deprecated

FYI I did not succeed to find an upstream for MimeMailParser, only copies outdated in the very same way.