Passage: In peacetime, the Bundeswehr is commanded by the Minister of Defence. In state of defence, the Chancellor would become commander-in-chief of the Bundeswehr.The role of the Bundeswehr is described in the Constitution of Germany as defensive only. But after a ruling of the Federal Constitutional Court in 1994 the term "defence" has been defined to not only include protection of the borders of Germany, but also crisis reaction and conflict prevention, or more broadly as guarding the security of Germany anywhere in the world. As of 2017, the German military has about 3,600 troops stationed in foreign countries as part of international peacekeeping forces, including about 1,200 supporting operations against Daesh, 980 in the NATO-led Resolute Support Mission in Afghanistan, and 800 in Kosovo.Until 2011, military service was compulsory for men at age 18, and conscripts served six-month tours of duty; conscientious objectors could instead opt for an equal length of Zivildienst (civilian service), or a six-year commitment to (voluntary) emergency services like a fire department or the Red Cross. In 2011 conscription was officially suspended and replaced with a voluntary service.

Question: Which system replaced conscription in 2011?
voluntary service