Raspberry Zero Email-Printer

I would like to get a raspberry pi zero following job to be done automatically: As soon as there is a new e-mail, it downloads the mail, parses the text and directly prints the text. Attachments shall not be handled. The connected printer is a little thermal printer. There is already a script and a guide how to set this up. [login to view URL] But since it is an old php version i dont get it running. So the goal of this project is to use the existing solution and get it working on a Raspberry Zero with Raspbian Buster. The job is finished with a new guide how to get it running. Thanks