Change mysql settings ( my.cnf ) using manual from https://mathiasbynens.be/
Fix your wordpress installation existing posts using ideas from this blog – https://theblogpress.com/. For some strange reasons old unpublished drafts on my blog written in cyrillic are broken!
If you have owncloud server installed, migrate all data and functionality to nextcloud. Now my personal cloud works under php 7.1 also.
Now site has almost everything up and running.
Still waiting for weathermap plugin to support cacti 1.0 plugin architecture!