555 v0.2.1

macOS: 555_…_universal.dmg (Apple Silicon and Intel). The app isn't signed by Apple: on first launch, right-click 555 → “Open”, or run xattr -cr /Applications/555.app.
Windows: 555_…_x64-setup.exe. If Windows says “Windows protected your PC”: “More info” → “Run anyway”.

Once installed, 555 updates itself.