METHOD FOR MIGRATING OR ALTERING A MESSAGING SYSTEM

A method for changing or migrating a voice messaging system comprises the steps of creating a new version of a mailbox for at least one user; and using the new version for a period of time before removing an old version of the mailbox. Significantly, the change or migration is effected such that there is substantially no system interruption. The changes may include making a software upgrade; moving a logical or physical device from a first location to a second location or from a first computer system to a second computer system; and making a change from a first version of the application to a second version. The migration may be a complete migration in which all devices are migrated or a partial migration in which only selected devices are migrated. Once the change or migration begins, any new inputs or calls to a device are routed first to the new application and, if the new application is not yet ready to receive the input, then to the old application. Alternatively, the sequence may be reversed and the new input calls may be noted first to the old application and then to the new application.