In many apartment buildings in Vienna, there are still old tenancy agreements with a category rent (tenancy agreement concluded before 1994). The amount of rent is determined by the respective category (A to D) and is adjusted according to the 1986 consumer price index. If inflation exceeds 5%, there will be a rent increase. In addition to category rent, tenants will be asked to pay a maintenance and improvement fee, the amount of which is also determined by law.