The current Ulysses version requires iOS/iPadOS 17 or later and macOS 13 or later. But what if your device does not support this OS version? In this case, you can download a compatible Ulysses version from the “Purchased“ section of the App Store, provided that you are using the Apple Account tied to the subscription. This Apple support article explains the exact way to re-download apps from the App Store.
Please note that you will only see the app if it is compatible with your device. For example, Ulysses must have already been installed once on a Mac that is connected to your Apple Account so that you can re-download the previous app version to your Mac now.
Since previous Ulysses versions do not include newer features, you may run into compatibility problems. However, you should be able to sync your sheets and groups across devices provided you use the same iCloud account for all of them.