Further to this announcement two significant issues have come to my attention (thanks Paul 🙂 ).
Two error messages you might see are: The each() function is deprecated
and create_function() is deprecated.
Both of these are significant issues, but there is a fairly simple short term method to avoid them if upgrading to 7.2 is important or necessary for you. That is to diable error reporting in your PHP configuration. These issues are both deprecated functions. Deprecated means they still work, but will generate warning error messages. By disabling “display errors” you simply don’t see the messages, and kiwitrees works normally.
If you can’t, or prefer not to disable error messages, then you will need to stay on PHP 7.1 and not use 7.2 yet.
I am treating these as my current top priority, and will release kiwitrees 3.3.4 as soon as these are fixed. Hopefully within the next week or so.