Hi Daniel,
I am the one managing the archival process and indeed, it was around end-2018 when the archival process just died (you can see the status here:
https://dumps.wmflabs.org/status.php).
The current status is that the software behind the archival process is being reworked and will come with features that I will be announcing once it is ready. The Wikidata JSON dumps will resume archival starting next week, so unfortunately all information between end-2018 till around October 2020 will be lost (unless someone has a copy somewhere). As for the dumps in 2017, there were other issues that caused the archival process to stall as well (you can see the list of available and archived dumps here:
https://dumps.wmflabs.org/wikidata.txt).
I sincerely apologize for the lost information. The new version that I'm currently working on right now will definitely be much better and more robust to handle failures.
Warmest regards,
Hydriz