Every platform, every install method, every workaround.
Choose installer OR portable. Portable is recommended (no install, no warnings).
APK install: enable "Install from unknown sources" for your browser, download the APK, tap to install. Or use the PWA for instant install via Chrome → ⋮ → Install app.
Unzip → right-click the app → Open → Confirm. Required because we haven't bought an Apple Developer cert ($99/yr) yet. PWA via Safari is the simpler alternative.
The signed IPA requires a Mac + Xcode + $99/yr Apple Developer Program. For now, install the PWA: open /sheets/ in Safari → Share button → Add to Home Screen. The PWA has every feature except true-native iOS notifications.
For now, use the PWA: open /sheets/ in Firefox/Chrome/Brave → install via browser menu. AppImage build coming — it's a single file, no install needed.
Microsoft discontinued Windows Phone OS in 2017 and shut down the Windows Phone Store in 2019. No active devices. Sorry — physically can't build for it. If you have a Windows Phone, you'd need to use the device's built-in browser to view PWA pages (likely won't render modern JS though).
BlackBerry OS was discontinued January 2022. No app store, no updates. Newer BlackBerry-branded devices actually run Android — those should install the Android APK fine.
KaiOS (the modern feature-phone OS in Nokia 8110, JioPhone) doesn't have a Chromium-class browser, so PDF rendering + Web MIDI + WebRTC features won't work. Not on the roadmap.