Valve’s Steam gaming store will drop support for macOS High Sierra and macOS Mojave early next year, effectively ending support for the last versions of macOS that could run 32-bit games, notes MacRumors.
Valve announced the change in a Steam support post: As of February 15th, 2024, Steam will officially stop supporting the macOS 10.13 (High Sierra) and 10.14 (Mojave) operating systems. After that date, existing Steam Client installations on these operating systems will no longer receive updates of any kind including security updates. Steam Support will be unable to offer users technical support for issues related to the old operating systems, and Steam will be unable to guarantee continued functionality of Steam on the unsupported operating system versions.
Unfortunately, macOS 10.14 was the last version to support running 32-bit games on macOS. Apple chose to drop support for 32-bit applications in macOS 10.15 (released 2019), and since many developers have not updated their games to support 64-bit executables, some games will effectively stop functioning on macOS. The Steam store will stop considering games that offer only 32-bit macOS binaries to be Mac compatible at the end of 2023. 98%+ of Steam customers on Mac are already running macOS 10.15 or newer. This means 32-bit only games and applications no longer run on your current operating system.
In order to ensure continued operation of Steam and new 64-bit games purchased through Steam, users on these older versions should update to a more recent version of macOS. We expect the Steam client and games on these older operating systems to continue running for some time. After February 15th, 2024, we will no longer support macOS 10.14 or earlier and we are unable to guarantee continued functionality of 32-bit macOS games after that date.
This change is required as core features in Steam rely on an embedded version of Google Chrome, which no longer functions on older versions of macOS. In addition, future versions of Steam will require macOS features and security updates only present in macOS 10.15 and above.
We strongly encourage all macOS 10.13/10.14 users to update sooner rather than later. Apple ended security updates and technical support for macOS 10.13 in December 2020 and for macOS 10.14 in October 2021. Computers running these operating systems, when connected to the internet, are susceptible to new malware and other exploits which will not be patched. That malware can cause your PC, Steam and games to perform poorly or crash. That malware can also be used to steal the credentials for your Steam account or other services.