In the docs (https://www.elastic.co/guide/en/kibana/current/index.html) there appears to be no reference whatsoever as to how to upgrade from one version to another.
Please clarify.
Which versions are you updating from/to?
Oops, sorry for missing that detail ! 
4.3.1-linux-x64 to 4.5
Should simply be a matter of taking your 4.3/config/kibana.yml and moving it into the 4.5/config directory. Please let me know if you run into any issues!
Hello,
I'm also upgrading and I have a problem with the .kibana index.
Elasticsearch from 2.1.1 to 2.3.1 and Kibana from 4.3.1 to 4.5.0, on Windows 7 x64.
I launched 2.3.1 nodes and indices migrates from 2.1.1 to 2.3.1 just fine, exept my .kibana index.
I moved the 4.3/config/kibana.yml to 4.5/config/kibana.yml but i didn't help.
When I have one 2.1.1 node and multiple 2.3.1 nodes, it hosts the .kibana index, and I can see its secundary shard jumping from 2.3.1 node to 2.3.1 node in a second, but never staying.
So now I must run 2.3.1 nodes for data, one or two 2.1.1 nodes to host the .kibana index, and kibana 4.3.1 to use kibana.
How can I migrate properly and not lose Kibana visus and dashboards?