I can’t download Procreat on my iPad

I have an iPad 4th generation and I recently tried to download Procreate, but the app wouldn’t allow me because I needed an newer iOS update. But when I went to update it said that the latest version had already been installed, which was the iOS 10.3.3. How can I update it and get a newer version? Do I have to do things through my pc or something or is it no way I can update it?