I’m not sure where you’re getting that. Xiamenese was citing KB, which is the forum handle for our company’s founder. Scapple is still in active development for both macOS and Windows.
That linked post by KB explains the changes the developers are making on the macOS side, with the goal of making an iOS version. As with Scrivener, that will need additional work to ensure the iOS version can play nicely with Scapple for Windows.
Please do keep in mind we’re a small company with two macOS/iOS developers and one Windows developer. Any changes or improvements take our team time, and we want to ensure we get major changes right.
I suggest setting a watch on the forum’s announcements page so you’ll see when beta versions for the Windows version are available.