Welcome back after 11 years 
I asked Chris what would be the response to your request above and this was his reply:
To run on Tahoe, or any of the recent MacOS versions, the app needs to be a 64bit app. Dramatica Story Expert, unfortunately, is a 32bit app and therefore cannot run on current versions of MacOS. We’ve been in a constant state of ‘catchup’ and because of that we’ve not been able to develop new features and capabilities for a number of years. Creating a 64bit version of Dramatica Story Expert requires us to completely rewrite the program for 64bit.
After many false starts and only partial successes, we have decided that we’re not going to release or further develop a Mac-specific version of Dramatica Story Expert for MacOS.
Instead, we have turned our efforts to the new platform independent subscription version at Dramatica.com, which is where all future development is expected to happen.
If you’d like to work with the older version of Dramatica Pro on Windows please let us know through the Write Brothers tech support site and we’ll send you a serial number for it.
If you have documents you’d like to have exported to .RTF or PDF files, please send them to us through the Write Brothers tech support site (link below) and we’ll convert them for you.
LINK: https://techsupport.screenplay.com/hc/en-us
Sincerely,
Chris Huntley
Write Brothers Inc.
On the platform side of things (the new “subscription” model), I think you’ll find it more than worth your time to check out. We identified several issues with the algorithms that calculated Storyforms incorrectly when we merged together, and patched them with the new setup and rollout.
That’s the very best thing about this kind of model, with your support (and the support of others) we can continue to improve and keep up with the times to offer the very best that Dramatica theory is capable of, which includes modifications to algorithms, new theory (the version from 10 years ago does not have the new Melanie-and-Chris approved Audience Experience appreciations!), and of course current and up-to-date Storyforms.
It’s important to understand too that you’re not “hostage” to the subscription, you can always start and stop given your writing process. ALL of your data will always be accessible to you even if you cancel your subscription.
If you have anymore questions about what is happening today in Dramatica in 2026 then feel free to ask away here. If referring to the legacy versions of Dramatica, please use the above link. Thanks!