20.07
Find your group and stay reachable — in a crowd or off the grid, even with no signal.
Sideloaded APK — allow installs from this source once in Android settings. Min SDK 26 (8.0+).
When cell towers are jammed, throttled, or unavailable, people lose the ability to find each other, call for help, or share proof of what's happening. 20.07 fixes that with zero infrastructure: phones relay for each other directly over Bluetooth. No SIM, no servers, no accounts — everything's encrypted under a key only your group holds.
Three solutions
Navigate
A live radar of your group around you — walk toward the dot, don't read a map.
SOS
An authenticated distress broadcast that hops phone to phone, distance shown in hops.
Incident photos
Photos encrypted and relayed across the mesh — proof that doesn't live on just one phone.
Why this exists
Cellular networks assume normal conditions. That breaks down in a specific, recurring set of situations, whether the network is overloaded by too many people or there was never much of it to begin with: natural disasters and blackouts, stampedes and crowd crush, festivals and events with no signal or no local data plan, hiking and remote areas with no towers nearby, and demonstrations where networks are jammed, throttled, or not trusted. In every case the same three needs recur — find your group, call for help, get incident photos out — and 20.07 does exactly that, phone-to-phone, with no infrastructure required.
Design choices
- No accounts, ever One QR code creates a group. No owner tied to it — removing one person doesn't expose or kill the group.
- Blind relay by design Every phone, even ones outside your group, carries your traffic — architecturally opaque to them, not just "encrypted so please don't."
- The radio ID itself rotates Your Bluetooth advertising ID changes every 60 seconds, so passive scanning sees a changing, meaningless value instead of a stable fingerprint.
- GPS never touches disk Lives in memory only — gone the instant the app is force-quit.
- Incident photos outlive any one phone Photos relay across the mesh as they're captured — copies exist elsewhere before any single phone stops being available.
- The app can disguise itself One switch shows the home-screen icon and notification as a plain utility app instead.
Build it yourself
git clone the repo, then from 20.07/: ./gradlew assembleDebug
builds the APK, ./gradlew test detekt runs the suite. Needs JDK 17 + Android SDK
(platform 34). Full steps in the README.