Jena 2.4 has been released:

http://prdownloads.sourceforge.net/jena/Jena-2.4.zip

Also available at the Jena User Conference :
http://jena.hpl.hp.com/juc2006/

== In this release:

Jena 2.4 introduces Assemblers (doc/assembler/assembler-howto.html), the
replacement for ModelSpecs.

Assemblers allow Jena models to be constructed from RDF descriptions.
Model components (eg database connections, reasoners, sub-models, prefix
mappings) can also be described. The mechanism for mapping from the
descriptions to the Java objects is generalised and user-extensible.

Both Joseki3 and Eyeball2 use the assembler mechanism as part of their
configuation control. ModelSpecs will be deprecated in future releases
of Jena.

Support for HSQLDB http://hsqldb.org/ has been added.
  This is a small,
100% Java database engine that can be used to give persistence to Jena
models.

Support for MS SQL Server has been added to the main codebase, including
use with MS SQL Server 2005 Express SP1.

Various minor bug fixes.

==== Notes

== JAR file changes:
    Added:    wstx-asl-2.8.jar
              json.jar
              iri.jar
    Removed:  stax-1.1.1-dev.jar
              jakarta-oro-2.0.8.jar
              
== N3 and Turtle

The syntax form  2.3  (that is, an unquoted number with a decimal point)
is now interpreted as being an XSD decimal, not and XSD double.  This
change is inline with changes to N3 (cwm) and Turtle definitions and is
the same as SPARQL.

2.3e0 remains an XSD double.

== SPARQL and RDQL

The SPARQL engine is upgraded to version 1.3.

The old RDQL API is deprecated - applications should migrate to the
package "com.hp.hpl.jena.query"

== MySQL

The reading of long literals has been fixed and applications can now
safely use the 3.1 series JDBC drivers.  There is no implications on
database schema.

Note that the 5.0.0-beta JDBC driver has a concurrency problems (MySQL
tracker 19416) although only in unusual situations with Jena. Setting
the "query only asserted" option enables use of the 5.0.0-beta driver if
necessary.