The translation of epiousios as 'daily' or ' supersubstantial' has been a matter of contention for a long time at least since St. Jerome translated it as supersubstantial in the Vulgate. Old Latin had cotidianum (quotidian) and it's also in the Gospel of Luke.
Jerome who wrote that he had seen the Gospel of the Hebrews said it read "Our bread for to-morrow give us today" (Panem nostrum crastinum da nobis hodie). He said he was translating the "Hebrew" word 'mahar' which he found in the place of supersubstantial. He however didn't believe it to be the authentic reading since he believed it contradicted the later passage in the sermon at verse 34.
The Greek word epiousios isn't attested anywhere else in Greek literature before the New Testament scriptures at least but a similar word, 'epiouse' is used in the book of Acts and is usually translated as the following or the next day.
http://biblehub.com/greek/1967.htm
http://www.earlychristianwritings.com/text/gospelhebrews-mrjames.html
http://biblehub.com/str/hebrew/4279.htm
Another thing that is different in some traditions is the rendering of forgive. Aside from the issue of the very nature of the word, in some Syriac texts the verse is rendered in a perfect or imperfect tense instead of the present tense so "as we forgave our debtors" or "have forgiven" in the Peshitta and "shall forgive" in old Syriac. Their rendering of epiousios or "daily" is also different ("that we need" or "of our need/necessity") Some commentators have believed the imperfect tense to make more sense and be perhaps the most authentic.
http://aramaicnt.org/articles/the-lords-prayer-in-galilean-aramaic/