Dear Support,
There was an App that aim was to try bring Dropbox back to NC, but Repo ist died (latest commit 2 years ago): https://github.com/icewind1991/files_external_dropbox
Nevertheless currently somebody registered/updated this application in Appstore https://apps.nextcloud.com/apps/files_external_dropbox with reference to old repo where nobody did any update.
It could be that somebody overtake the App name and try to hack our NCs. I did not install this app, but have one manually installed from the repo and have had update notification. Please check it!!!
I would love it if this is false alarm.
UPDATE: Link in apps.nextcloud was updated to other repo, that is a fork from initial: https://github.com/DJaeger/files_external_dropbox/