In order to activate the “Filter” button, please navigate to Theme Settings -> General -> Mobile bottom navbar -> to the “Select buttons” field add the “Off canvas sidebar” item.
After we looked into the situation, we found the problem with the bottom tab resulting from the lack of the necessary code. We feel terrible about this mistake and in our next update it will be fixed.
Kindly accept our sincere apologies for the inconvenience caused to you and don’t hesitate to reach out if you have any additional questions.