As per a comment from Tom Brown in the original spec, we propose that timestamps be changed from POSIX time to RFC 3339 for potential human-readability and clarity (to avoid millisecond confusion).

Furthermore, I would propose that the time zone always be set to "Z" (i.e. UTC) to further prevent confusion.

i.e. 2016-01-13T21:19:33Z instead of 1452719973