Just noticed in the preview that there was a Latin version of the Oath.
Except it is entitled Lex Hermæ, which is definitely not right. Lex, the law, should not be used for anything order related.
As the Oath is an Oath, you would likely want to go with Ius Iurandum (the thing being sworn), which wound commonly be shorted as Ius, so Ius Hermetis or something like that with the correct derivative of Hermes.
This is a clear typo that shouldn’t be hard to fix, please fix it before release 
Why? Seriously.
Answering for @Sobek - we are talking about it in the discord; Lex implies an already existing authority and "constitutional" (in the most general of senses) rule; the Oath of Hermes cannot be a "Lex" because is the founding principle of the Order. It is more appropiate to call it "Ius Hermetis" which translates much better to the idea of an Oath (taken before the gods, for example, though the Hermetic Oath takes the Arts themselves as witness).
I'm not so clear about the Tribunal (Great or Peripheral) resolutions - we are still talking about them. I'm partial to use the terminology of "Mos"; as in "Mos Maiorum" (Customs of our Ancestors). As a founding principle is already established, "Lex" might be appropiate, though.
Yes, I can see that perspective. I do remember going round and round over the best translation for "Oath" in this context. I think I came down on the side of "lex" because it is a written rule, and not in itself the foundational authority of the Order. That comes from the magi gathered in Tribunal. (And, in theory, the Grand Tribunal could change the oath.) I think "ius" was the other main option I considered, although this is pushing thirty years ago, when my Latin was a lot less rusty than it is now. I think I decided against it because this isn't the abstract right, it's the written manifestation of it.
Incidentally, I looked up Hermes to find out how it got declined, and my dictionary said it declined to "Hermae" in the genitive singular — Wiktionary agrees. "Hermetis" is wrong if we are going with classical Latin. The declension of Greek loan words was often rather peculiar.
I would strongly suggest Ius Hermeticum instead of Lex Hermae.
Ius coming from ius iurandum here, the text of an oath - so translates well to Oath as well as to human made law.
The individual Hermes has very little to do with the Oath of Hermes - and his name in Latin soon turned into Mercurius anyway. The oath in question is also neither sworn by nor to Hermes.
We should rather use the adjective hermeticus here, as the Oath of Hermes is far rather an Oath of the Order of Hermes or Hermetic Oath.
Latin far more than English punishes imprecision of a concept. Lex Hermae reads either as Law of the Greek God Hermes - or worse, as the Law of the Lawn Ornament.
Both are clearly not meant.
As far as I can tell, the word "hermeticus" is medieval Latin, which is too late for a name given in the eighth century, and which did not at that point have the meaning of "concerning the Order of Hermes". The Founders were referring to the Greek god, as not-exactly-Mercury. There wasn't really an Order of Hermes to give it a different name when they were naming the Oath.
I could be persuaded on Ius if lots of people think it is better, though.
One problem here is that translation is always a matter of judgement, and my Latin is no longer at the level it was when I made the translation. This makes it difficult for me to assess the suggestions.
We certainly have the Liber Hermetis, Latin in 5th century AD, which is part of Hermetica, a collection of works supposedly tracked back to Hermes Trismegistos.
These are indeed all very early medieval terms - also the Hermetis as the genitive of Hermes.
Hermeticus as a reference to Hermes the God or Hermes Trismegistos and inspired by the Greek term Hermetika is at the very least a simple Latin derivation.
As a minimum, Ius Hermetis would be short, safely early medieval (5th century AD) Latin, referring to early "Hermetic" books and close to the English Oath of Hermes. Both the English and the Latin reference to Hermes are also equally dubious about whom they refer to.
But Hermae is also short, clearly old enough, and references the in-game fact that the Founders chose Order of Hermes because they were derived, but distinct, from the Cult of Mercury, and not because of the real-world roots of the term "Hermetic". Obviously, the real-world choice of terms goes back to Hermes Trismegistus, but the translation of the Oath should defer to in-fiction reality.
Incidentally, according to Copenhaver's modern English translation of the Hermetica, the first Latin translation of the whole set was fifteenth century, so I'm not sure how far back we can push "Hermeticus". Latin authors seem to have ignored the texts until the twelfth century, and the collection is apparently Greek, and possibly eleventh century. "Hermetis" does seem to be clearly early medieval, but I don't see a strong advantage over "Hermae", especially as the Latin of the Order has been clearly established in the game as classicising.
I should split this out. The Latin matters, but it is a distraction from the press release.
Yes, the whole. But we have (see my reference above):
The Liber Hermetis ("The Book of Hermes") is an important work on astrology laying out the names of the decans (a distinctly Egyptian system that divided the zodiac into 36 parts). It survives only in an early (fourth- or fifth-century CE) Latin translation,[14] but contains elements that may be traced to the second or third century BCE.[15]
BTW, references 14 and 15 are to Copenhaver.
So there we have a Latin author who latest in the 5th century translated parts of the Hermetica. Bonisagus could have read that ... and known it was from the Greek Hermetika. 
It is old, but I do not know of any classical or classicising examples. Old Stowasser, which claims to list any words in the typical classical authors, does list Hermae for the sculptures, but not Hermes at all.
Yes, but was it called the Hermetica at that point? That's what it is called now, and I bet it was called that in the 15th century, but does it go back earlier?
In game, it almost certainly exists by the beginning of the ninth century as the adjective for the Order. But that's just a little too late for the name of the Oath.
Does he list any Latin parts of speech for Hermes? Here, we may run into a problem with the need for a Latin Hermes that is not Mercury.
"My dictionary appears to be wrong" may be enough to justify the switch to Hermetis.
Incidentally, I remembered one of the reasons behind "Lex". The Oath of Hermes is also the Code of Hermes. It's the central bit that the Peripheral Code is peripheral to. At the time I was translating it, it was only referred to as the Code of Hermes — also calling it the Oath of Hermes appears to be an ArM4 innovation, which postdates the translation by several years. I still remembering dithering about it, but I bet the English "Code" pushed me towards "Lex" rather than "Ius".
Would people be happier if we changed the English back to "Code of Hermes"?
Some things to consider are
Just how good at Latin were the Founders? Might they have used bad grammar?
What kind of Latin did they know? Classic Latin was kind of dead at that point, and early medieval Latin was likely in a bit of flux, and not all that consistent over all of Europe.
I can't answer that question for the collection of works. I am sure that it was called Hermetika in Greek at the time of Bonisagus.
But going from a name Hermes to the adjective Hermeticus is simply following other well known Latin examples that form a pattern: Attica => Atticus, Macedonia => Macedonicus, Plato => Platonicus, Sappho => Sapphicus and so on. Bonisagus could have followed that, especially if inspired by Greek Hermetika.
I think the way it is written, as a first person oath, justifies moving to Ius, I don’t have strong opinion on the genitive to use for Hermes.
And for the same reason, that text should remain the Oath of Hermes.
The name Code of Hermes can then be used to refer to the more general knowledge encompassing the interpretation and enforcement of the Oath, and the order rules and customs.
But fundamentally, the root of all the legal structure of the order is an Oath, freely taken individually by each member, which is quite different from a law enacted by an authority.
I think ErikT's points are good. My Latin is wobbly, and mostly ecclesiastical, but two points:
First, the name given to the Oath may not be the name it was originally given. "Code of Hermes" may be a slightly later designation, in which case Lex would make perfect sense, in the context of an already-thriving legal structure.
Second, no super strong opinions on Hermae, but it doesn't seem obviously atrocious Latin. The grammatical arguments don't seem decisive to me. I can think of at least one example of the word - the Pastor Hermae, or Shepherd of Hermas, an early Christian work. The genitive there is to mark the author of the work, which doesn't precisely fit the case. But I would submit that in any case it is unusual even in English that the Code is referred to as "of Hermes", so that strangeness may as well remain in Latin
Also, there’s « legem » in the part about making apprentices sweat on the oath, that also suffers from the same issue.
The Latin version has the Bonisagus knowledge sharing clause right after the apprentice clause, and the clause on giving apprentices to Bonisagus is missing.
Overall, I think it shouldn't be too hard to find someone who has some serious expertise in Latin (professionally) in the community to help with that translation. I love the idea of having the original Latin text, but it would be disappointing if it had avoidable mistakes.
That would work as a justification for keeping "Hermeticum" in the absence of any early attestation of the Latin. It's not a reason to change.
Overall, I don't think the arguments against "Hermae" are strong enough to justify a change. It is clearly a correct possibility for the genitive form, and Latin speakers just didn't name Hermes often enough in Latin to give us clear guidance on native usage, as far as I can tell.
Or maybe Guernicus insisted on calling it "Lex", to make it sound more intimidating and encourage magi to obey the letter of the Code. That would be entirely in character, given the way he is described in True Lineages.
I think "lex" is clearly a legitimate choice as a translation of "code", and even the ArM5 text refers to the text of the oath as the "Code of Hermes". "Ius" could also be justified, but I'm not sure the arguments for a change are strong enough.
When I made the translation, I had graduate-school-level Latin. (I was participating in reading groups where we read medieval philosophy in Latin to discuss the philosophy, and I didn't need dictionaries or cribs.) So, we need a Latin teacher or a researcher who specialises in Latin per se. They might exist in the community, but I am less sanguine than you about the possibility of finding them. (Arabic — now that we could do.)
They are in the wrong place in the English. I'll have them moved.
It's the oath as sworn by Bonisagus (it has that date in, as well). My Latin is no longer good enough to supplement the translation.
Well, if you insist that Guernicus must have pushed for Lex, go for changing the English title to Code of Hermes.
(Even better, add a footnote (or a sentence in the main text body) saying that Guernicus is responsible for the shift in usage away from Oath of Hermes, if that’s workable with the layout)
Tmk Bonisagus of ArM did invent the Latin names for the Order of Hermes and the Oath of Hermes in the 3rd quarter of the 8th century AD. He would not have referred to the discarded Roman god Mercurius, but to a godly patron of magic of occult Hellenistic tradition: Hermes-Thoth-Trismegistos, which he interpreted anew and in a more classical sense than others.
So Bonisagus had to choose between directly addressing that patron, like the 4th to 5th century translator of the Liber Hermetis did, or refer to him obliquely, as Hellenistic authors did when coining the Koine term Hermetika for the literature referring to that patron. The name Hermes by Stowasser does not appear with Latin classical authors, who still refer to Mercurius. A genitive hermae is easy to confound with the classical Latin genitive of Herma - so is weird for a patron of the occult.
AFAICS that makes the Oath of Hermes either Ius Hermeticum or Ius Hermetis. Personally I'd like Ius Hermetis best, because the unclear, non-classical use of a genitive form for an oath not sworn to or by Hermes appears also in Liber Hermetis, which is a text neither written by nor about Hermes either.