What page are you getting that off of?
That seems like a general note for the platform-wide update. The documentation for each platform program page has extended details about what updates were made to that program.
EG filemaker server 14.0v4 for mac:
or filemaker pro 64 bit for PC:
On the downloads page, read the full "release notes" links to the right of the download link for full details.
thanks, but uh ... still haven't figured out what the 'changes to the interaction between clients and host' means ...
TL;DR - There were a number of possible changes that could encompass that generalization. Read the "release notes" pages for the software you are using for further details. All the updates are explained at greater length under those pages.