Circulation:
Weighting of the individual fields of the in-database circulation and holds rules can now be configured, rather than using hard-coded values. This allows the importance of each field to be adjusted as needed.
The in-database circulation rules support "fall-through" wherein some information can be left out of more specific rules and filled in from less specific rules. For example, disabling fines for staff could be accomplished with a single rule setting only the fine rate and/or max fine rules without having to duplicate all duration related rules in the system.
Grace periods are now stored in the database and set via circulation rules, rather than passed into the fine generation code, and can thus differ between different rules. They are also no longer a number of fine intervals, but a separate interval of their own.
General Staff Client Improvements:
The client supports new hotkey sets that are selectable per workstation. In addition there is now a toggle for temporarily disabling hotkeys available on the toolbar and in the admin menu.
The client has a second toolbar for cataloging functions as well as options for presence and size of icons and presence and position of labels, all selectable per workstation.
I dunno how to categorize:
Patron registration now supports "Suggested" fields that are configurable per library. In addition, library settings allow for adjusting required fields and specifying validation regular expressions for many fields in patron registration.