Will not install latest update. Emailed the developer but got no response. They have probably already been paid for this complete rebuild so aren't bothered that it doesn't work.
Update now working it's a lot better than old version faster with more information. (thank you for contacting me )
Can't install new version on Marshmallow. Error -504
V2 hopeless...won't install
Android 6.0.1 unable to Update
Latest version can't install. On Marshmallow.
Fixed installation issues with Marshmallow and later platforms
The official guide app to Wales’s public forests and National Nature Reserves.