A few weeks ago I posted about Red Grid MGRS, a free 10-digit MGRS navigator for iOS (Android shipping soon!). Based on your feedback I shipped a bunch of new updates:

Topographic map layer with contour lines (OpenTopoMap) alongside standard and dark tactical tiles

Meshtastic LoRa mesh integration — connect to a $20 radio over BLE for off-grid position sharing. Had to write a minimal protobuf encoder from scratch since there's no React Native SDK

Three map styles you can cycle through and download for offline use

Fixed the iOS BLE state machine issue where CoreBluetooth starts as "Unknown" and silently blocks scanning

Getting Meshtastic integration to work was a rabbi thole, but by far the most interesting technically. The protocol uses protobuf over BLE with a specific handshake. There was no documentation for third-party integration, so I worked from the protobuf definitions and the official iOS app's behavior to get this working.

Still zero network calls for core functionality. Still no tracking. Open source.