The other projections use OpenStreetMap and Natural Earth data. We do not plan to make frequent updates to the tiles, since the geological features of most interest to us do not often change.
WGS84 tiles are from OpenStreetMap as of 2017-08-28, and Natural Earth version 2.0.0.
I understand that there aren't frequent updates for the osm tiles, and this isn't anything urgent at all, but I just wanted to let you guys know that we noticed some islands in the Oslo fjord are missing on the GBIF maps (https://github.com/gbif-norway/helpdesk/issues/87#issuecomment-1048759038), whereas they're now present in open street map, if I'm looking at the right thing.... https://www.openstreetmap.org/#map=12/59.8901/10.6046&layers=H. So at some point I guess new geological features do get added, and an update might be useful :)
From https://tile.gbif.org/ui/:
I understand that there aren't frequent updates for the osm tiles, and this isn't anything urgent at all, but I just wanted to let you guys know that we noticed some islands in the Oslo fjord are missing on the GBIF maps (https://github.com/gbif-norway/helpdesk/issues/87#issuecomment-1048759038), whereas they're now present in open street map, if I'm looking at the right thing.... https://www.openstreetmap.org/#map=12/59.8901/10.6046&layers=H. So at some point I guess new geological features do get added, and an update might be useful :)