Apple is contacting podcast producers requesting that they optimize the metadata for their shows — or risk having them removed from Apple’s podcast service.

The cautionary email mostly concerns guidelines on including detailed, nonredundant written descriptions of episodes. However, the Apple Podcasts email contains a few surprising directives — like the fact that titles should not include numbers. Provided that’s read as intended, this could cause a few problems!

As AppleInsider, which first reported the news, points out, many podcasts use episode numbers to make clear which installments people are listening to.

Others, like design podcast 99% Invisible, include numbers in their show titles. And some others use numbers to indicate the date a certain show was recorded on.

It remains unclear which (if any) of these will be allowed or disallowed under Apple’s new podcasting rules.

A fresh focus on Apple Podcasts?

It’s not clear whether Apple is tightening up on podcast metadata as simple housekeeping or for other reasons. Apple helped kickstart the podcast boom with the iPod and iTunes Store in the mid-2000s.

However, despite recently spending more than $1 billion on original video content and heavily investing in music, it has largely left the Apple Podcasts service alone.

Meanwhile, Spotify — Apple Music’s biggest rival — is supposedly embracing podcasts as a possible new growth area. Will Apple show refreshed interest in its podcast service as a result? We’ll have to wait and see.