Some time ago (October 2006), we released 'Lightbulb', a simple SAML 2.0 service provider/relying party implemented in PHP, as a proof-of-concept, to show that it was indeed possible to write a 'pure' (no custom modules required) SAML 2.0 implementation in PHP.
Later, Lightbulb became an OpenSSO Extension, and was used by
Andreas Solberg at FEIDE as the inspiration for simpleSAMLphp - a much more complete SAML 2.0 implementation, again in PHP, but this time including identity provider functionality, Shibboleth 1.3 and more.
Andreas has done a great job, devoting considerable time and effort to simpleSAMLphp, to the great benefit of the wider SAML 2.0 community. Over the months, simpleSAMLphp has become widely deployed in the academic community, to the extent that there are now events such as simpleSAMLphp workshops.
Consequently, we have decided to mark the OpenSSO SAML2/PHP Extension as 'deprecated' in favor of simpleSAMLphp. The old code will be left in place in CVS, but there is now a prominent README directing people to simpleSAMLphp.
Long live simpleSAMLphp!
Kind of like seeing one of your kids moving out of the family home and starting their own life, I guess...