Is the .afpub format proprietary to serif? In other words, if I took it upon myself to reverse engineer the .indd format, would I be able to convert it to a format that was directly readable by Affinity publisher? I'm just wondering if the affinity formats are open source or a closely guarded secret. I have a hunch those adobe files look an awful lot like a .pdf file. I know for a fact that if you have an .AI file and you want to view it on a computer without Adobe Illustrator, but you do have a pdf viewer, then all you need to do is rename it. i.e. FileIWantToSee.ai gets renamed to FileIWantToSee.pdf. Voila, it will (probably) work. Reverse engineering the .indd file format might not be as simple as that, but it also might not be impossible as well. There must be some method to Adobe's madness and if you ever decode it you'll need to interface with Affinity's madness. Sounds like fun.