Valve published a support document detailing the end of Steam support on two old macOS versions: High Sierra (10.13) and Mojave (10.14). On February 15, 2024, Valve will stop issuing updates (including security updates) for its game client and will stop providing technical support.
According to Valve, the main reason behind the decision is the end of Google Chrome support on macOS High Sierra and Mojave. Several parts of the Steam client rely on embedded Chrome, which will soon stop working on Apple"s old operating system. In addition, Valve says future Steam versions will depend on features and security updates available only in macOS Catalina (10.15) and newer.
The end of support does not mean Steam and downloaded games will stop working on February 15, 2024. Customers will be able to continue using the platform and play games for some time, but Valve cannot guarantee continued functionality after the specified date. In addition, the lack of security updates may expose old operating systems to additional security risks.
The latest Hardware & Software Survey from Valve indicates that 1.19% of all Steam customers use macOS to access the platform. Over 98% of them use macOS 10.15 and newer. Therefore, the change is unlikely to upset a large number of Steam users. Still, there is one notable problem with Steam dropping macOS 10.13 and 10.14: 32-bit games.
macOS 10.14 Mojave was the last operating system with support for 32-bit applications and games. macOS 10.15 Catalina removed 32-bit app support, rendering plenty of games unusable on macOS. Those playing games on Mac now have to make a tough choice: continue using an unsupported OS or abandon 32-bit games.
Valve says Steam will stop accepting 32-bit-only games at the end of 2023.
As a reminder, Windows 7, 8, and 8.1 will lose access to Steam on January 1, 2024. Unlike macOS High Sierra and Mojave, Steam will not run on old and now-unsupported Windows versions starting next year.