I usually avoid GoHub because it started as a click-bait website, but someone on Discord linked to this article and it explains pretty well:
https://pokemongohub.net/post/news/pokemon-go-maps-and-trackers-go-down-after-a-forced-0-95-3-api-update/
Forced update. New API and security system has to be reverse engineered again. Could maybe be 3-5 weeks based on past outages.