Every standard is subject to systematic review, normally 5 years after their publication, in order to determine whether it should be confirmed, revised/amended, or withdrawn.
Some standards require regular updating provisions, to take into account the feedback and to support their implementation. These provisions are developed within maintenance agencies.
UNM is responsible for two European maintenance agencies and one International maintenance agency dealing with the following standards:
Click above on the standard reference for a direct access to the corresponding maintenance agency