I got caught by this and would like to offer a suggestion on how to avoid further confusion...  I believe the label "TimeZone Update (Admin)" is somewhat ambiguous.  Hindsight is 20/20.  How about changing this label to something of a wider context, like "Edit/Modify Events" and then expand on the point of adjusting the time zones across all existing events (as such) within the administrative screen with a button so make it so.  Cheers!  and thanks for the mod.  ;)  ~ Adam

Joiseystud,

maybe I should answer, since I did an indeep investigation last year on this subject.

There is no problem storing all datetime values in UTC (this does not need to be calculated, it is provided by .Net framework and SQL Server) and converting it to user time zone. But there are still two problems remaining:

• the UserTime class in core is misleading developers when using Method names like CovertUserTimeToServerTime, which actually adds the difference between portal default timezone and individual user time zone. There is actually a confusion between physical server's timezone and portal default time zone, which needs to be solved. This issue can be solved (I started with an internal proposal to convert all datetime values to UTC), but this needs additional effort.
• the second issue sounds minor, but has major effects: DNN is DST agnostic. This means
  a) there is no switch in timezone settings, to distinct between normal and summer time (DST) and
  b) our currect timezone table does not provide any assistance for automatic switches.
  What are the options to solve this?
  a) might be resolved by rather easily by adding a DST checkbox, allowing manual adjustments - in site settings, but also required for all users in their profiles.
  b) is nearly an ineffordable task without external support - remember how often Microsoft provides upgrades for the windows DST adjustments (at least twice a year). .Net 3.5 provides new classes to access windows time zones, but unfortunately DNN cannot require .Net 3.5 to be installed.

We am still looking for a suitable solution, maybe with different functions depending of the framework version used, but this still needs a lot of effort.