
There are a few places with rules such as "... lastFri 0:00 ..." that should be "... lastThu 24:00 ..." One possibility is to rewrite the rules that way; doing so buys error messages from pre-1998 versions of zic. Another possibility is to rewrite the rules as "... lastThu 23:59:59 ..." which works with pre-1998 versions of zic but is a second off. A third way is to use 24:00 and, where it is used, include a comment about either upgrading zic or using the 23:59:59 dodge. I'd appreciate any insights on how to go forward.
I think it'd be better to have the rules state 24:00 if the transition is at 24:00 (instead of either stating 23:59:59 or using the 23:59:59-means-24:00 solution). I'd expect that users of an 11-year-old version of zic will be able to do the simple replacement of 24:00 with 23:59:59 on their end, especially if there are comments by the 24:00 values, and it's better to optimize for what I assume is the much more common case of a user with a more recent version of zic. In particular, I feel like if either 23:59:59 solution is used it will become standard practice, leading to either one second errors or added interpretation complexity forever while providing benefit to a small and continually shrinking set of pre-1998 users. - Adam