I have a few Macs that are not on macOS Sierra for various reasons - some cannot run the latest OS. Hence, I am hoping Scrivener 3.0 can create files that are usable by earlier versions of Scrivener. Will that be the case? Or is it that once a file is converted, it will be un-readable by earlier versions of the software?
Unfortunately that was not a possibility to achieve. It would be one thing to have a 2.x format save function in 3.0—even that would be a huge amount of code bloat for something that will eventually not be a problem—but to have 2.0 understand and work with 3.0 projects would require a massive overhaul to an end-of-line program. You will need to keep projects held back if you intend to use them with older Macs, or just hold off on upgrading until you can get all of your systems up to 10.12. Sorry for that!
Hi Amber
I note what you have said above, but I came across the following article:
http://www.inkitpub.com/2017/08/12/what-does-scrivener-3-0-mean-for-scrivener-for-ios/
It states: “It does not matter if you are using current versions of Scrivener (2.8.2.1 for Mac and 1.9.7 for Windows) or Scrivener 3.0 with the new project format – both old and new versions sync with Scrivener for iOS. You do not need to worry about if your project on your iPad or iPhone is the older or the newer version. Scrivener for iOS works seamlessly across both versions and protects the integrity of the project structure when you are back on your desktop.”
Essentially, after the file has been converted, I want to know if I can use version 2.8.2.1 on one Mac, and version 3.0 on another Mac, and edit the same new-format Scrivener file on Dropbox using both of these Macs that are running different versions of Scrivener 2.0 and 3.0 ?
That’s a good question. Basically the iOS version uses its own little corner of the project to do its work, so for the most part it doesn’t really mess with the project itself except to read from it. Every file you change gets saved separately in its corner, and it saves its own settings separately from the Mac/PC settings. It’s ability to read either format is thus very simple: all it needs to do is find content files where they are supposed to be, and while that has changed, it’s not a terribly complicated matter to look up a .txt or .rtf file on the disk in different places depending on the format.
So fundamentally the project itself will either be 3.0 or an older version. Whether the iOS version of Scrivener has its own little corner of the universe within it matter not. Thus once a project is upgraded to 3.0, while the iOS version can use it, that doesn’t make it magically possible for 2.8 to use it or vice versa.
Thus: you can have a 2.8 project you’ve held back for whatever reason, and iOS can use it. And you can have a 3.0 project just used by the other computer, and iOS can use it—but those projects will only be accessible to their respective versions on the Mac itself.
Hi Amber,
For clarification regarding Mac: Will v3.x be able to seamlessly use v2.x projects? Or is there some kind of conversion procedure needed?
At least the beta, Scrivener 2 projects have to be converted to be used in V3 (which duplicates the project so the original V2 project is retained in the same directory). Conversion works very well, and the problems going from V2 to V3 are to do with the user carrying expectations from working in V2 to V3 (compile being the biggest change); the more advanced the user the harder it will be to adjust!!! 
Thanks for your help nontroppo. I’m not advanced at all. Haven’t explored compiling yet so I’ll be going into that process from scratch.
Thanks again
Leo
So Leo, you have a distinct advantage compared to us old Scrivener dinosaurs!!! 8)
I’ve just never written anything worth compiling. But now I’m feeling the mojo with NANOWRIMO upon us and hope Scrivener can help me achieve my goal - to finally finish something. You might say I’ve suffered a severe case of writers block for the past 25 years…lol
A quick note on this: Scrivener 3 uses an updated .scriv file format, so when it opens a Scrivener 2 file, it upgrades it to the new format. At that point, the file cannot be opened in Scrivener 2 again, because Scrivener 2 doesn’t know about the updated format. However, you will be able to export from Scrivener 3 to Scrivener 2 format, so you could always do that if you needed to use the project on an older machine or with an older version.