The latest update had a lot of drastic changes to the system -- unfortunately the changes are too big for the old saves to be kept intact, we really tried our best to transfer the former saves... but yeah it didn't work out well in the end. We think this is still the best decision so at least you could play all characters in the future without having to clear data/ loose anymore progress for any of them. All the waifus now belong to you! xD
On a serious note, we could at least promise you, and assure you that it's the final save data wipe. We have no more planned huge changes to the structure after this, and we're pretty much satisfied already. We expect taking quite a bit of a blow from reviews from the forced wipe, but please do rate/give us your honest thoughts about the recent update so we could improve our services.
That's all, and sorry for the inconvenience everyone. Nonetheless please have a great day and enjoy the newly added features.