As I'm sure you know there have been multiple problems with restoring chat history in your new app. I will be patient on this.
What I want to address here is that you are restoring chat history going back only one year. This is totally inadequate. As someone who frequently travels, any chats that I had with people in different cities more than a year ago are now gone. I imagine you're dealing with your own storage capacities but I think you should restore at least 2 years of chat history