Assuming you’ve made sure both devices are running .90 already, one other thing to be aware of is that in .90 the sync and search actions will only work if you don’t supply any arguments (eg /sync works, but /sync?x-callback-success=… does not). I will fix this in a future update.
Thanks, I just noted that my iPad mini had .89 installed. After upgrading, it works perfectly now, thank you for your answer and long term contributions!