I think PARI has a particular convention about even vs odd minor version numbers, so 2.7.x and 2.8.x don't work the same.
See http://pari.math.u-bordeaux.fr/faq.html#versioninfo
I think PARI has a particular convention about even vs odd minor version numbers, so 2.7.x and 2.8.x don't work the same.
See http://pari.math.u-bordeaux.fr/faq.html#versioninfo