In 1955, Tore Wretman commissioned architects Peter Celsing and Nils Tesch to modernize the premises and turn Operaterrassen into a permanent banquet hall. The result was a unique combination of materials such as copper, brass, and mahogany with a sleek design that still impresses to this day.
During the summer of 2016, Operaterrassen was renovated to optimize it for meetings and conferences. This included laying a new roof, which was done according to the same design created by Celsing - the roof is meant to reflect the water of Stockholm's ström. These modernizations make Operakällaren a perfect venue for both historical and modern events and give a unique feeling to every meeting or celebration.