Always check the project's description for its target edition before downloading.
For those searching for the most efficient way to learn or reference these rules, several community-curated and official PDFs are invaluable: Age of Darkness Rulebook - The Horus Heresy - First Look horus heresy 20 rules pdf better
When an errata changes a point value or a weapon profile, you can type a note directly over the outdated rule in your PDF. This ensures you never play an illegal list by mistake. Always check the project's description for its target
Play space is valuable. A tablet takes up a fraction of the space required by an open, double-page hardcover book, leaving more room for your models and dice rolling. double-page hardcover book