it superficially appears to me that Time::Zone contains hard-coded time-zone offsets, which is probably not a sound algorithmic approach.   Whereas DateTime::TimeZone appears to make use of .tzinfo files, which (at least on Un*x-ish systems) is the standard approach that is used by “the operating-system in general.”   Therefore, I have high confidence that .tzinfo files will be available that know about this change, whereas for the other Perl module it’s anybody’s guess.   I think that there ought to be “one source of Truth,” which in this case would be .tzinfo files.   Therefore, of the two approaches, I would favor the latter.   (Disclaimer:   I have not looked into the issue closely, and don’t plan to ...)