I updated WooPress to version 4.0 and find out some problems:
1. Header ‘Fixed navigation’ does not work.
2. When customers click ‘add to cart button’ on products page layout, nothing happens. It is not possible to understand were products added to cart or not. Please see video
https://borovichi.sushifoods.ru/
video link https://www.dropbox.com/s/tmifh48k57cg5pr/WooPress%204.0%20bugs.mov?dl0