In the Puggalapaññatti of the Therevada Abhidhamma at Pp2.4 there is preserved a version of the Patipada that appears to be earlier in form to the one at DN2.
It exhibits several differences, all of them appearing to preserve elements that are simpler and less elaborated than the familiar example in the long discourses.
DN2, after the decision to go forth on the part of the householder has:
So evaṁ pabbajito samāno pātimokkhasaṁvarasaṁvuto viharati ācāragocarasampanno, aṇumattesu vajjesu bhayadassāvī, samādāya sikkhati sikkhāpadesu, kāyakammavacīkammena samannāgato kusalena, parisuddhājīvo sīlasampanno, indriyesu guttadvāro, satisampajaññena samannāgato, santuṭṭho.
Once they’ve gone forth, they live restrained in the monastic code, conducting themselves well and seeking alms in suitable places. Seeing danger in the slightest fault, they keep the rules they’ve undertaken. They act skillfully by body and speech. They’re purified in livelihood and accomplished in ethical conduct. They guard the sense doors, have mindfulness and situational awareness, and are content.
Compare with the equivilent passage at Pp2.4:
So evaṁ pabbajito samāno bhikkhūnaṁ sikkhāsājīvasamāpanno
Having thus gone forth, one who has adopted the training and livelihood of the monks…
So Pp2.4 seems to preserve a text from before the pātimokkha was added, which makes sense since the pātimokkha is simply another more elaborated list of rules than the one given in the silas of DN2, and therefore probably post-dates it.
The next major difference is that Pp2.4 has only the shorter section on ethics, not the medium and long, again suggestive of the fact that the latter where added to the patipada of DN2 as time went on (and followers found more and more ways to avoid the spirit of the instruction).
The next difference is that all the metaphors are absent, both for the hinderances and for the jhanas. Again, this is suggestive that these where added early to the patipada but are not necessarily original to it.
Finally the most striking difference is that the psychic powers are completely missing, the sequence goes from a short section of ethics to a sense restraint to situational awareness, to a simile free overcoming of the hinderances, to a one paragraph for all four jhanas (again with no similes) to recollection of past lives, to seeing the arising and passing of other beings, to the ending of the defilements. (again, all without similes)
The whole thing is bracketed by the notion that this person is
(at the beginning)
Kathañca puggalo neva attantapo ca hoti na attaparitāpanānuyogamanuyutto, na parantapo na paraparitāpanānuyogamanuyutto? So anattantapo aparantapo diṭṭheva dhamme nicchāto nibbuto sītībhūto sukhappaṭisaṁvedī brahmabhūtena attanā viharati.
and
So anattantapo aparantapo diṭṭheva dhamme nicchāto nibbuto sītībhūto sukhappaṭisaṁvedī brahmabhūtena attanā viharati.
Such a person, free from self-torment and from tormenting others, dwells in this very life, satisfied, at peace, cooled, experiencing happiness, and living with a mind that has attained the state of Brahmā.
(at the end)
I would, returning to the pātimokkha question, even go so far as to argue that "establishing the practice of the beggers way of living (bhikkhūnaṁ sikkhāsājīvasamāpanno) literally is the
“pāṇātipātaṁ pahāya pāṇātipātā paṭivirato hoti nihitadaṇḍo nihitasattho lajjī dayāpanno sabbapāṇabhūtahitānukampī viharati adinnādānaṁ pahāya adinnādānā paṭivirato hoti dinnādāyī dinnapāṭikaṅkhī, athenena sucibhūtena attanā viharati abrahmacariyaṁ pahāya brahmacārī hoti ārācārī paṭivirato methunā gāmadhammā musāvādaṁ pahāya musāvādā paṭivirato hoti saccavādī saccasandho theto paccayiko avisaṁvādako lokassa.”
of the remainder of the paragraph.