The MSISDNs in your subscriber lists are constantly changing. Subscribers change numbers, subscribers switch mobile operators and other events occur that impact the accuracy of your lists. Operators and industry groups have mandated that content provides maintain up-to-date subscriber lists.
The Universal Deactivation Manager (UDM) service provides you with an aggregate view of changed or deactivated subscriber MSISDNs on a daily basis. The UDM service combines deactivation feeds from mobile operators and combines them into country specific files for use as you update and manage your subscriber lists.
Read the Universal Deactivation Manager User Guide attached below for more information about the UDM service: