SmartGo Kifu has been discontinued and replaced by SmartGo One. With SmartGo One, you’ll get stronger computer play, more pro games, more problems, dark mode, iCloud syncing, and much more. And the books from Go Books are fully integrated.
You can read a blog post on the improvements in SmartGo One compared to SmartGo Kifu.
If you bought SmartGo Kifu, feel free to keep using it. You can have both SmartGo Kifu and SmartGo One installed on your device.
If you recently bought SmartGo Kifu (in 2021 or 2022), please send me your receipt, and I’ll get you an extended free trial of SmartGo One.