Deal with very old versions

old versions are not always easy to sort auomatically. Specify a manual order?
Better: provide release dates for each version (see below), then automatically sort releases by date

Release dates

tell import-zips which dates to use, e.g. via a hash table in import-zips

Or perhaps have a file "date-VER.txt" which contains an ISO 8601 date; it is used if present, otherwise the date is computed automatically as before
some of the .zip files for older versions sent by Richard Koch are "polluted" in the sense that they contain ctimes / mtimes in 2016. -> create a script which reads those .zip files, and computes the "latest modification" from those, ignoring any dates past a certain point (say 2015+... TBD).

Then let that script generate VER/date.txt files