From Wikipedia...
"Redevelopment for 2007 season
With a new financial backer, the renovation started on November 6, 2006 and finished in May 2007, costing around €19 million.[12]
Formula 1 returned to Spa for 2007, with a modified track layout. The Bus Stop chicane was moved back towards Blanchimont and the La Source hairpin moved forward. This allowed more space for the new pit lane. The modifications gave a longer start/finish straight"