Service updates in ElastiCache
ElastiCache automatically monitors your fleet of caches, clusters, and nodes to apply service updates as they become available. Service updates for serverless caches are automatically and transparently applied. For self-designed clusters, you set up a predefined maintenance window so that ElastiCache can apply these updates. However, in some cases you might find this approach too rigid and likely to constrain your business flows.
With service updates, you control when and which updates are applied to your self-designed clusters. You can also monitor the progress of these updates to your selected ElastiCache cluster in real time.