I'm sure what's involved is a pretty minor change inside the
TVM▸ 's application, and nothing to do with the
OS▸ , or whether the app will run under it. But organising that is far less simple, as can be seen below:
If you want to know what fares data looks like, you can sign up to a free licence and get some.
RDG‡ do give a little information on this, though the document defining the file formats of these "RJIS Datafeeds Interface Specification For Fares and Associated Data" is an
ATOC» one dated 2004. This says the two main fares data files are 100MB and 50MB, and the restriction file is 475 kB (or they were then).
Of course that's not what gets downloaded onto a TVM; it will be digested into something more specific. But no doubt the applications running in the machines were designed together with the pre-processing with that form of data as part of the specification. That definition knows nothing about ticket types - they are just specific values of data fields. Time restrictions are dealt with via restriction codes (the same codes you see on a ticket, surely). Each restriction code leads to a list of atomic restrictions, and one field in some of those (date band and calendar records) is a length-7 field called DAYS:
A set of 7 markers each set to Y or N,
representing the days of the week. The first
character represents Monday. If the marker
= Y, then the restriction applies on this day
of the week, between the dates in
DATE_FROM/DATE_TO. If the marker
is N, then the restriction does not apply on
this day of the week, between the dates in
DATE_FROM/DATE_TO.
So if the TVM application applies that based on the true day-of-the-week value, nothing in its downloaded data tables can alter that. It would need changed software in all TVMs so the DAYS data is be redefined as the "applied day value" and some new data field introduced to say how to derive this applied day from the true date (not just day-of-the-week).
That doesn't sound too hard, and if that field itself is unchanged then unmodified machines would simply ignore the change. But the fact that the definition is so old suggests that it's not something RDG would undertake lightly. Are they justified? I really don't know. But the "who's going to have to do what?" question is likely to be important.