Here is a deep dive into why Slack killed support for macOS 10.13, the security implications, and the few remaining options for users stuck on legacy hardware. Slack follows a predictable lifecycle policy. Generally, the company supports the current major version of macOS and the previous two. When macOS Ventura (13.0) dropped, macOS 10.13 fell off the cliff.
While High Sierra was once a stable workhorse, running it today means looking at a frustrating message in the Slack sidebar: slack mac 10.13
Apple stopped issuing security patches for High Sierra in . If you are running 10.13, your machine has known unpatched vulnerabilities, including the infamous CVE-2019-8518 (a logic issue allowing malicious applications to bypass Gatekeeper). Here is a deep dive into why Slack
Slack in a browser (Chrome or Firefox) has no such restriction. Open your browser, navigate to app.slack.com . It is slower, notifications are clunky, and you cannot drag files easily, but it works perfectly. This bypasses the Electron dependency entirely. When macOS Ventura (13
However, for the IT manager or the freelancer on a budget: Chrome on High Sierra still receives security updates (for now). Keep a pinned tab for Slack.
By refusing to run on High Sierra, Slack protects itself from liability. If a hacker used an unpatched macOS kernel bug to inject code into Slack’s memory, users would blame Slack, not Apple. Modern apps refuse to run on EOL (End of Life) systems to maintain their security reputation. For the user, the experience is abrupt. You open Slack. You see the splash screen. Then you see: Can't open Slack You have macOS 10.13. Slack requires macOS 10.14 or later. If you have an old version of Slack cached, you might get the "Update Required" yellow banner. However, the API servers eventually reject the old client, returning an http_platform_failure error. You can read messages, but you cannot send them, join huddles, or upload files. Workarounds (And Why They Fail) For users clinging to a 2012 MacBook Pro that cannot officially upgrade to Ventura, what are the options?