Apple recommends that users such as DJs avoid Catalina until developers update their apps, as the option to export music libraries as XML files has been removed
and it's breaking some apps Adrian Kingsley-Hughes / ZDNet : macOS Catalina — Should you upgrade now? Filipe Espósito / 9to5Mac : macOS Catalina breaks compatibility with DJ apps that use iTunes libraries Danny Zepeda / iMore : macOS Catalina removes iTunes... and XML file support for DJ apps Mike Wuerthele / AppleInsider : Apple warning DJs to stick with macOS Mojave for now Tweets: Rob Lowry / @robertlowry : ATTN: the death of iTunes is also relevant and horrible for music supervisors https://twitter.com/... Matt Deco / @mattdeco : Catalina removed the way apps like Serato and Rekordbox read your iTunes library. Reminder: As a software person involved in music stuffs, I suggest running MacOS 1-2 major versions behind what is current. I currently run High Sierra, for example. https://www.theverge.com/... Dani Deahl / @danideahl : So uh, if you're a DJ and have put tons of time into sorting music in your iTunes playlists for whatever software you use ...maybe don't upgrade to Catalina just yet https://www.theverge.com/... Rich Burroughs / @richburroughs : TIL that DJs use XML files. https://twitter.com/... Frank Denis / @jedisct1 : And 32-bit apps can't run any more. My scanner, for example, will become a brick > macOS Catalina is available today. https://www.apple.com/... Dave Zatz / @davezatz : I just want webp previews in iOS file manager. https://twitter.com/...
Context & Ripple Effects
Catalina is the release that dissolves iTunes into separate Music, TV, and Podcast apps — a breakup reviewers have largely welcomed — but the release of the new apps also deleted the XML library export DJs relied on. With the export gone, apps like Serato and Rekordbox can no longer read a user's iTunes library, and Apple's own advice is to stay on Mojave until developers update.
The warning lands on the same day as the broader Catalina reviews, which already flagged rough edges like overbearing security prompts and thin Catalyst apps. It also compounds Catalina's earlier removal of 32-bit app support — two compatibility breaks in one release, with Apple telling a professional segment of its user base to defer the upgrade.
First-order effects
- DJs and music supervisors who upgrade lose library access in Serato, Rekordbox, and similar apps immediately, since the XML export that let those tools read iTunes collections no longer exists.
- Apple is formally splitting its Mac base: it is recommending a professional cohort stay on Mojave, an unusual admission that its own flagship OS release is not safe for all users on day one.
Second-order effects
- DJ software developers are forced to rebuild library integration against Apple's newer Music app interfaces rather than file exports, shifting the cost of the iTunes breakup onto third-party app makers.
- The break pushes DJ tooling toward streaming-native integration — the direction Apple itself later validated by opening Apple Music's catalog to DJ software and hardware platforms like Algoriddim's djay Pro and AlphaTheta.
Third-order effects
- If the pattern holds, Apple will keep trading file-based interoperability for first-party API and streaming access, making each macOS release a compatibility event that professional users must schedule around — a discipline already visible in the 32-bit removal and later in the transition to Apple-designed Mac chips running iOS apps natively.
- Platform owners increasingly mediate what professional software can touch: the durable lesson is that library formats and exports are provisional, and vendors building on them need migration paths the OS maker doesn't control.
The trend: Apple is dismantling file-level interoperability in favor of its own APIs and streaming integrations, with DJ software as both an early casualty of the iTunes breakup and, eventually, a beneficiary of Apple Music's platform opening.