Broadcom pulls the VDDK: the first thing that breaks is not your migration, it is your backup
In late August the download pages for the Virtual Disk Development Kit started returning a 404, with no announcement and no deprecation notice. The coverage has read it as "leaving VMware just got harder", and that is half true: it depends where you are going, because Proxmox VE's ESXi importer does not even use it. What almost nobody has looked at is Broadcom's exact wording — "no longer available for use or download" — or the place where that library has been working for twenty years without anyone looking at it: inside your backup.