Mac users who plan to upgrade to Catalina, the latest version of Mac OS, won't be able to use the desktop version of uTorrent. Both uTorrent and BitTorrent Mainline are not compatible with the new operating system and users will be automatically upgraded to the browser-based "Web" clients instead.

uTorrent for Windows first came out in September 2005. Soon after, it became the most widely used torrent client, which it still is today.

Initially, Apple users were left out, but after three years BitTorrent Inc. released their long-awaited version for Mac OS.

While official numbers are not available, uTorrent likely never gained the impressive market share it enjoyed on Windows. This is, in part, was due to the fact that there were already several established Mac torrent clients around, including Transmission and Vuze.

In recent years there’s been very little progress on the Mac development front. The last client update dates back to last year, and there is virtually no discussion going on in the official Mac forums. It was also excluded from the recent BitTorrent Speed release, which is Windows only.

That said, something big is expected next month. BitTorrent Inc. just announced that the desktop versions of uTorrent and BitTorrent Mainline won’t be available on the new Mac OS Catalina (version 10.15 and up). Instead, all users will be updated to the browser-based web clients.

The reason for this is fairly simple; uTorrent Mac is only available as a 32-bit application, while Apple’s upcoming release of Mac OS Catalina is only compatible with 64-bit apps.

“Therefore, in early September, we will automatically update µTorrent Classic for Mac to our newest torrent downloader and player, µTorrent Web for Mac. This is necessary to ensure that our torrent downloading software continues to work seamlessly with Catalina when millions of users update to the new version,” BitTorrent Inc announces.

“We will start updating users in early September. If you are using µTorrent Classic for Mac version 1.87 or earlier version, you will automatically get upgraded to µTorrent Web for Mac.”

It’s no surprise that support for 32-bit applications will end on the newer Mac OS. This has been known for a while and, for this reason, a 64-bit version of uTorrent was put on the feature request list last year. However, that request didn’t receive an official response.

As a result, all users of the new Mac OS Catalina will have to move their torrenting activity to the browser, or find an alternative client. Users who haven’t updated Mac OS to Catalina can continue to use the desktop version.