Ports of Milsko are grouped into three "tiers" in terms of their support.

- **Tier 1**: Before every new release of Milsko, these platforms will be tested to make sure they have full support, and the CI will test them.
- **Tier 2**: These might be outdated or not updated in awhile, they might only compile under a specific version/commit of Milsko. Authors of these backends will be made aware of these updates.
- **Tier 3**: These are outright unfinished. Only use these if you're a developer.

Currently, the Tier 1 backends are:

- Windows 9x+/NT 4.0+
- Any Unix/Linux system that supports X11 or Wayland.

There are currently no Tier 2 backends.

Tier 3 backends are:

- Mac OS X 10.4+ with Cocoa
- Mac OS 7-9, PowerPC (68k support not planned).
