So…
I am maybe two weeks away from the end of a big project, that I will resume at some point this summer.
I’d really want to upgrade to 3, but just in case, I’ll probably finish the aforementioned project in 1.9 while starting other projects in 3.
But if my Scrivener 3 is an “upgrade”, will my Scrivener 1.9 be still usable?
Yes. Just stick to 1.9 until you’re ready to move on.
Yes. I have licensed versions of both v1.9 and v3.0 running on my PC.
Just be sure to install Scrivener 3 in a different program folder from Scrivener 1.9. The install process should take care of this automatically, as it defaulted for me to a program folder named Scrivener3.
After you install Scrivener 3, it will become the Windows default program for Scrivener’s .scrivx project files. This means if you are in the habit of launching a project by double-clicking the .scrivx file or a shortcut to the scrivx file, you will no longer be able to do that for your v1.9 projects. Instead, you should launch Scrivener 1.9, and then select and open the project from within Scrivener.
Best,
Jim