This idea has been merged into another idea. To comment or vote on this idea, please visit DHPLANNER-I-171 Add custom maps WMS / WMTS.
Support for custom background maps would be really great!
Maybe you could add the support for RasterTileMaps (like the SQLite MBTiles-Format or for a simple folder based tile store on the sd card) or a custom WMS/WMTS Link. Tile-Format-Info could be found under the following link: https://www.maptiler.com/google-maps-coordinates-tile-bounds-projection/
Thanks a lot!