ECSAs can be disconnected from the Platform during the upgrade of. This will allow them to continue processing on the current version throughout the upgrade and the downtime will be minimized. The ECSAs will be upgraded at restart.

 There are certain prerequisites that need to be fulfilled in order to safely complete the upgrade of:

• The traffic protocol must support failover. If not, restarting the ECSAs may cause loss of data, unless the traffic is redirected first.
• You cannot keep ECSAs running when there have been changes in the storage models for Aggregation, Inter Workflow, Usage Management, PCRF, or Routing Control. When the platform is upgraded and the ECSAs are restarted, existing data is converted to the updated storage model. If a problem occurs at this point and a downgrade must be performed, the previous version will not be capable of handling the data generated by the new version.

For information about changes in the storage models, see the Release Notes.