In 2006 the Archbishops of Utrecht and Canterbury celebrated together in Freiburg im Breisgau, Germany, 75 years of the Bonn Agreement in the context of the 29th International Old Catholic Congress (IAKK).
The Swiss Willibrord Society normally celebrates a "Willibrord Day" every year. This is normally in October or November, close to St. Willibrord's Day (7 November).