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* api-change:``docdb``: [``botocore``] This release adds Global Cluster Failover capability which enables you to change your global cluster's primary AWS region, the region that serves writes, during a regional outage. Performing a failover action preserves your Global Cluster setup.
* api-change:``ecs``: [``botocore``] This release introduces a new ContainerDefinition configuration to support the customer-managed keys for ECS container restart feature.
* api-change:``iam``: [``botocore``] Make the LastUsedDate field in the GetAccessKeyLastUsed response optional. This may break customers who only call the API for access keys with a valid LastUsedDate. This fixes a deserialization issue for access keys without a LastUsedDate, because the field was marked as required but could be null.
* api-change:``s3``: [``botocore``] Amazon Simple Storage Service / Features : Adds support for pagination in the S3 ListBuckets API.