Did you just run Screenwriter or Dramatica on MacOS 10.13.x High Sierra and get an alert: Dramatica Story Expert or Screenwriter "is not optimized for your Mac"? OR, are you considering installing pre-release (beta) versions of 10.14 "Mojave"?
Movie Magic Screenwriter and Dramatica Story Expert are presently 32-bit Carbon applications. Apple is planning to end support for all 32-bit applications, however the news that just was confirms at Apple's Worldwide Developers Conference in early June was that 32-bit Carbon apps will CONTINUE to work with the next major version of MacOS, version 10.14 ("Mojave"), which ships in late September 2018. Apple will continue 32-bit support until MacOS 10.16, which will ship in September of 2019.
Write Brothers is working diligently so our software will be 64-bit and ready before Apple ends 32-bit support. We hope to have those versions ready in the fall of 2018.
However, it is important to understand that you will not lose the ability to run Movie Magic Screenwriter or Dramatica Story Expert while your computer is using any version of MacOS High Sierra 10.13.x, or the released version of MacOS 10.14 Mojave, no matter how many updates of High Sierra or Mojave Apple pushes to users.
ONE CAVEAT: Please do NOT install early public release beta versions of MacOS Mojave. It isn't stable yet, and Screenwriter 6.5 has a few issues with the beta of Mojave on some computers.
So there's nothing to worry about until you proactively choose to install the NEXT version of MacOS, version 10.14 "Mojave", which won't be available as fully tested software until at least last September.
Warning about public testing of pre-release versions of MacOS 10.14 "Mojave":
Beginning in June and continuing through September, Apple will begin testing the next version of MacOS, version 10.14 "Mojave". PLEASE DO NOT INSTALL PUBLIC BETA VERSIONS OF MACOS 10.14 "Mojave" or your installed copy of Movie Magic Screenwriter and Dramatica Story Expert might cease to function!
Users of Screenwriter on High Sierra should already have upgraded to Screenwriter 6.5, and be running the latest updated version, 22.214.171.124. Users of Dramatica Story Expert on High Sierra should also begin migrating to the free update to version 5.3. Run HELP > Check for Update on Screenwriter and DRAMATIC STORY EXPERT > Check for Update to see if you have the latest versions of our software.
We will keep you informed via email (and automatic update notices) as to when it will be safe to install Screenwriter 6.5 and Dramatica Story Expert 5.3 on MacOS 10.14 Mojave.
NOTE that Apple's alert is only shown the first time you launch a 32-bit app on High Sierra 10.13.4 or greater, or on Mojave 10.14.x.
What If I Continue to Use MacOS 10.13 High Sierra, or 10.12 Sierra, or 10.11 El Capitan, or 10.10 Yosemite (and the final release in September of 10.14 Mojave)?
So long as you continue to use MacOS 10.10 through 10.13 (and 10.14 in September 2018), your 32-bit software will continue to work as it does now. You cannot be affected by the phasing out of 32-bit applications unless and until you upgrade your Mac to run MacOS 10.15 which hasn't even been announced and which won't be expected until the September 2018.
Will there be other benefits to a 64-bit version of Movie Magic Screenwriter / Dramatica Story Expert?
Yes. All 64-bit applications are fully Retina enabled (higher resolution graphics), and are generally faster and capable of using more memory.