Migrating Indicies from Kibana 6.x to 7.x

Hi,
I'm working on migrating my indicies while upgrading to kibana 7.x.
I have been looking for a list that contains all the migrations changes but did not found any place that contains them (such as working with references instead of ids and _type changes to _doc instead of doc and etc).
There is any place that I can find all the changes instead of investigating them by myself?

Thanks!

The Upgrade Assistant helps you prepare for your upgrade from Elasticsearch 6.x to Elasticsearch 7.0. To access the assistant, go to Management > 7.0 Upgrade Assistant .

The assistant identifies the deprecated settings in your cluster and indices and guides you through the process of resolving issues, including reindexing.

Before upgrading to Elasticsearch 7.0, make sure that you are using the final 6.7.x minor release to see the most up-to-date deprecation issues.

You can read more here: https://www.elastic.co/guide/en/kibana/6.7/upgrade-assistant.html

hope this helps
Thanks
Rashmi