What version of DiveView do you have

I have v2.00 - doesn't show any available update when I check.  I'm in US.

I have V2 as well, says it's up to date on the watch.
Where do you see DiveView in Garmin Connect?

I see version 5.0 for Dive Sites in GarminExpress, which is different from DiveView as I understand it. It fails to update for me too.
(I wish we could remove CourseView, golfing, maps)

You are correct in Garmin express it says update available Dive Sites V 5   Is available but never updates?

Just checked I don't have Dive Sites 5 on the watch, and express says there is an update (Dive Sites 5)but does not install it?

So my actual question is what is the difference between Dive Sites and DiveView maps? Is dive sites now obsolete?

Dive View maps are depth contour charts.  If you view the map in certain activities (such as single-gas, apnea, boat, etc.) and in covered locations (certain coastal waters) they are an automatically visible layer (unless they are disabled in the activity map settings).  They appear to cover most of the United States coast along with some international coasts (unfortunately they don't seem to cover much of the Caribbean, hopefully coverage will be expanded).

www.garmin.com/.../

Dive Sites are a collection of dive site names and locations (GPS coordinates) saved as POIs.  They can be accessed through activity Navigation-->Points of Interest-->Dive Sites.  Dive Sites works perfectly on my MK2S but do not appear under Points of Interest on my MK3i.  Given that discrepancy and the issue with Dive Sites not properly installing in Garmin Express, I suspect Garmin still needs to properly configure the MK3 Dive Sites software.

www.youtube.com/watch

support.garmin.com/.../

I submitted a support request with Garmin. They said there is a known issue with Dive Sites that they are working on resolving.

I am getting a similar problem when I try to update Dive Sites and it never updates (seems to install... unplug watch, plug in again, prompts me to install same update). However, on my map details, it shows dive sites not installed. That's a bit different than what someone else was experiencing.