There are missing features in UI7 as well ... It's really something between an alpha and beta test.
I have a test system ... on it I am on a test version ... newer than the current UI7 release ...
My test system would crash after about 7 minutes after making any changes ... turns out they found they forgot to change some code that my system tripped regularly.
The current version I am testing with solves that problem, but has a different set of bugs ...
i.e. there are a lot of land mines in UI7 still ... I have not even considered moving my personal house system to UI7.
Unless you do not mind spending hours trying to figure out why something doesn't work and how to work around it ... I would stay on UI5.
One of these days UI7 will be a quality release with a good probability that your system will work as expected when you upgrade. It'a just not there yet.
If you do upgrade ... then DO NOT COMPLAIN about bugs and how to convert back. If you upgrade you are asking to be a beta tester and you should expect problems.