src/timezone/README saith
When there has been a new release of Windows (probably including Service Packs), the list of matching timezones need
tobe updated. Run the script in src/tools/win32tzlist.pl on a Windows machine running this new release and apply any
newtimezones that it detects. Never remove any mappings in case they are removed in Windows, since we still need to
matchproperly on the old version.
We have certainly not been doing that on a regular basis (as best I can
tell, no such changes have been made since 2010). Does anybody who uses
Windows want to deal with it? Or at least do it once so that our Windows
TZ info is less than 5 years out of date?
If we got this done in the next couple weeks, any resulting changes
could go out in 9.6rc1. Given that we've not done this routinely,
that seems like a better plan than having them first hit the field
in minor releases of stable branches.
regards, tom lane