While browsing: https://www.gpo.gov/fdsys/bulkdata/BILLS/115/1/hr
I see the following entries (subset):
BILLS-115hr70eh.xml 06-Jan-2017 03:32 0.04 M
BILLS-115hr70ih.xml 04-Jan-2017 05:23 0.04 M
BILLS-115hr70rfs.xml 07-Jan-2017 05:00 0.04 M
While via the UI I can guess via the timestamps as to which is newest, there does not appear to be a programatic way to do so. The suffixes (eh, ih, rfs) seem random and arbitrary, and the user guide for BILLS does not indicate what the suffixes mean, or if there's any way to tell what order the revisions are.
I would suppose I could tell by timestamp, but, as mentioned above, that's only visible in the UI of the website. If I were to download the zip file, BILLS-115-1-hr.zip, all of the files have the exact same timestamp with each other.
Even more strange, it is now 11PM EST on Tuesday, January 10th, but all of the files in the BILLS-115-1-hr.zip file that I just downloaded right now have a timestamp of January 11th, 2017, 3:44am, which is in the future for me. So I would imagine your server or build machine that generates the zips is somewhere many hours in the future (England?) or has an incorrect system clock.
It might be reasonable to have your build machine preserve timestamps of the files when generating the zips.
I now see that dc:date2017-01-05</dc:date> is in the XML, however, some files have that tag empty. (See view-source:https://www.gpo.gov/fdsys/bulkdata/BILLS/115/1/hr/BILLS-115hr70eh.xml). Is it fair to assume that an empty tag means 'initial revision' ? Perhaps this should be documented.
Final Question: Once the ammendment process begins, is a new revision generated for each new ammendment? Or is it one new revision / xml file generated per day, regardless of number of ammendments approved?