Version 2 introduces a new Ansible Interface and Inventory. That means you can use the syncer now as Ansible Inventory Source, and also the information can contain data you read from your Checkmk installation. All other Params can be configured with rules.
Also, the Frontend now previews all parameters so that it is no longer needed to click inside a rule.
The CLI Entry point is now not longer flask, but ./cmdsyncer. All Params are grouped now, that means you need to adapt your cron jobs. But this makes the way to more planned features.
Under the Hood also, a lot has changed. You will find new Match Types and all functions are now completely separated. This you won't see at first, but will also help in the next features. The Ansible feature was the first who made use of this change.