When you create a first level Druid and select Animal Companion as your Nature's Bond PCGen them allows you to create your Animal Companion.
In building this Animal Companion, however, it incorrectly allows you to take feats that have a +1 BAB requirement.
See: http://www.d20pfsrd.com/classes/core-classes/druid/animal-companions under feats.
"Note that animal companions cannot select a feat with a requirement of base attack bonus +1 until they gain their second feat at 3 Hit Dice."
These are not rules updates, these are core rule that have never changed as far as I know.
I will see if I can find a copy of the 1st printing to validate....mine are the most up to date PDFs.
Ah, excellent. Duly noted (For both issues). I'll see about addressing this soon. (I checked, the wording exists in the 2nd printing and 4th, I don't know if I have a 1st... When that book was coded up it was the German prerelease version.
Thanks for your assistance, the issue will be rectified shortly (Give me a couple of days).
You can download the 1st to 6th edition change list. Animal Companion rules around INT and limitation of feats/skills have NEVER been changed. The only changes in the page ~50-55 range are around giving low light vision to some animals and referring to Handle Animal instead of the Bestiary.
These are all bugs.
Due to the state of the Pathfinder Set (Major overhaul) I can't easily get the updated files to you without risk of breaking your version of PCGen.