Get Wisp
Invite only. Get a link from someone already in, then create your account in the app.
No iPhone app yet. Vote for it.
Installing
Mac: unzip, drag Wisp to Applications. The first time, macOS may say it can’t check Wisp: open System Settings › Privacy & Security and choose Open Anyway.
Windows: unzip anywhere and run wisp-app.exe. If SmartScreen stops it, choose More info › Run anyway.
Android: open the APK and allow installing from that app when asked. Play Protect may offer to scan it; either choice is fine.
New versions show up in the app as an Update button.