@Denis_Lamanov, Thank you for your response. I am aware about this documentation. But i mentioned few queries and hoping some comment in response of each query. Specially with point 2 and 3.
No, Configuration files won't be upgraded you need to do it manually this process as there are some breaking changes and you need to take care the same also.
Yes, new version will be installed but you need to configure you parameter manually as per your old configuration file. However, if you change the configuration in you upgraded version there may be some "breaking changes" which needs to be taken care. Please perform the same in Test environment first.
Yes, In this version elasticseach has provided ILM also to user with atleast a basic license. By Default some components of ELK stack is using ILM. You can refer the below documentation for more clarification about ILM and Curator.
Apache, Apache Lucene, Apache Hadoop, Hadoop, HDFS and the yellow elephant
logo are trademarks of the
Apache Software Foundation
in the United States and/or other countries.