Thanks to our intrepid former ArM5 line developer David Chart, there's now a brand new list of updated ArM5 errata up on our website. You can find it here: https://www.atlas-games.com/arsmagica/arm5errata
Also new for ArM5 is the Grand Grimoire of Hermetic Spells, courtesy of Slerotin. You can find that here: https://www.atlas-games.com/atlas-cms/resources/pdfs/the-grand-grimoire-of-hermetic-spells.pdf
Again, thank you both for your excellent contributions!