The changes in the Derby 10.1.3.0 release since the 10.1.2.1 release include
over 100 individual fixes to various issues. Among these are:

  - Improved network server reliability, memory usage, and tracing facilities
  - Numerous fixes to XA behavior
  - Improved query performance for UNION queries and subqueries
  - Better handling of text encoding on systems with non-native ASCII encodings
  - More reliable behavior of scrollable insensitive result sets
  - Updated documentation
  - and many others

For a complete list of changes in the release see the release notes:
http://issues.apache.org/jira/secure/ReleaseNote.jspa?version=12310616&styleName=Html&projectId=10594&Create=Create