Update to 2.7.6.
Changes according to http://soprano.sourceforge.net/node/62:
- Support for the new SPARQL 1.1 DELETE statement which omits the graph to delete from for faster removeAllStatement execution in the Virtuoso backend.
- Support for the new default graph query result format of Virtuoso >= 6.1.5.
- Fixed apidox generation with Doxygen 1.8.0.