Synology has not yet pushed through our changes onto their distribution system.
As soon as everything pushes through all the hosts, Yes you can enable auto update.
Everyone will need be aware to manually get the 64 bit during this transition.
As part of the complete PMS build and repository system overhaul currently being done, all this is already configured to happen naturally. Had DSM 6.2 Update 2 not surprised everyone, you would never have been interrupted or likely even noticed the changes
The bottom line is:
32 bit PMS will no longer run on any 64 bit Synology NAS.
Here’s the forum announcement at the top of the server-synology
tag. DSM 6.2 Update 2 Announcement