With the Optional Upgrade Sequence feature, you can upgrade your core Communication Manager before upgrading your Survivable Remote Servers, formerly known as Local Survivable Processors (LSP). This sequence of upgrading has a limitation of configurations not synchronizing between the upgraded core Communication Manager and yet-to-be-upgraded Survivable Remote servers (LSP).

With the Optional Upgrade Sequence feature, you can have your core Communication Manager and Survivable Remote Servers (LSP) in different compatible versions.

• Supported versions of Core Communication Manager: Release 10.1.3.3 and later versions, Release10.2.1 and later versions.

• Supported versions of Survivable Remote Servers (LSP): Release 8.1.3.x, Release 10.1.x.

Traditionally, the existing upgrade sequence requires that all the Survivable Remote Servers (LSP) are upgraded before the core Communication Manager. In environments with a large number of survivable remote sites, the upgrade of the core Communication Manager has to wait until the end of the Communication Manager upgrade to use the latest features and fixes. With the Optional Upgrade Sequence feature, you can upgrade your core Communication Manager to the latest software version and use the latest features and functionalities of the upgraded software before you upgrade your Survivable Remote Servers (LSP). The Optional Upgrade Sequence feature ensures that the Survivable Remote Servers (LSP) running a lower software version continue registering to the core Communication Manager running on a higher version. However, the configurations on the core Communication Manager do not synchronize with Survivable Remote Servers (LSP) because of the difference in the software versions. Any administrative changes to the upgraded core Communication Manager are unavailable to the Survivable Remote Servers (LSP) running on a lower software version. The core Communication Manager generates a warning File synchronization (FSY) alarm for the software version mismatch. The core Communication Manager clears the warning alarm after you upgrade the Survivable Remote Servers (LSP) to the same or a higher software version than your core Communication Manager. The administrative changes are also available after the upgrade. Use Optional Upgrade Sequence if you do not expect changes at the branch locations. Select Survivable Remote Servers (LSP) for later upgrades such that they will not be impacted by the limitations of Optional Upgrade Sequence feature.

While you use the latest features from the core Communication Manager, you can continue to upgrade your Survivable Remote Servers (LSP) to the same or a later software version than your core Communication Manager. For example, if you want to upgrade to Avaya Aura® R10.2 which offers Trellix Antivirus support, identify the Survivable Remote Server (LSP) locations where you do not expect administrative changes and upgrade them after you upgrade your core Communication Manager. The upgraded core Communication Manager can utilize the Trellix Antivirus feature at the main location. Note that the configurations from the upgraded core Communication Manager do not synchronize with the yet-to-be-upgraded Survivable Remote Servers (LSP). The yet-to-be-upgraded Survivable Remote Servers (LSP) can register with the core Communication Manager.