Update 1.10.0-upgrade-guide.html.markdown (#1511)

website/docs/guides/1.10.0-upgrade-guide.html.markdown

@@ -20,7 +20,7 @@ The Terraform MongoDB Atlas Provider version 1.10.0 has a number of new and exci
 - You can now manage [Cluster Outage Simulations](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/#tag/Cluster-Outage-Simulation/operation/startOutageSimulation) with [`mongodbatlas_cluster_outage_simulation`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/cluster_outage_simulation) 
 - You can now enable [Extended Cluster Storage Sizes](https://www.mongodb.com/docs/atlas/customize-storage/#minimum-disk-capacity-to-ram-ratios) in [`mongodbatlas_project`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/project). This setting allows M40+ clusters to be configured with storage greater than the standard maximum (up to 4TB for M40, 8TB for M50/M60, and 14TB for M80+). Clusters with extended storage sizes must be on AWS or GCP, and cannot span multiple regions. 
 - You can now leverage the [`PrivateEndpoint.srvShardOptimizedConnectionString`](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/#tag/Clusters/operation/createCluster) parameter in [`mongodbatlas_advanced_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/data-sources/advanced_cluster) and [`mongodbatlas_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/data-sources/cluster) Data Sources. This is a private endpoint-aware connection string optimized for sharded clusters that uses the `mongodb+srv://` protocol to connect to MongoDB Atlas.
-- You can now leverage the [`retainBackups`](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/#tag/Clusters/operation/createCluster) parameter in [`mongodbatlas_advanced_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/advanced_cluster) and [`mongodbatlas_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/cluster) Resources. Set to true to retain backup snapshots for the deleted M10+ cluster. The default value is false.
+- You can now leverage the [`retain_backups_enabled`](https://www.mongodb.com/docs/atlas/reference/api-resources-spec/#tag/Clusters/operation/createCluster) parameter in [`mongodbatlas_advanced_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/advanced_cluster) and [`mongodbatlas_cluster`](https://registry.terraform.io/providers/mongodb/mongodbatlas/latest/docs/resources/cluster) Resources. Set to true to retain backup snapshots for the deleted M10+ cluster. The default value is false.
 
 
 **Changes**