PBM-1389 Documented limitations for ops for MongoDB 8.0 (#211)

PBM-1359 Documented limitations for ops for MongoDB 8.0

modified:   docs/features/point-in-time-recovery.md
	modified:   docs/features/selective-backup.md
	modified:   docs/usage/start-backup.md

docs/features/point-in-time-recovery.md

@@ -54,11 +54,15 @@ If you just enabled point-in-time recovery, it requires 10 minutes for the first
 
     If you [reshard :octicons-link-external-16:](https://www.mongodb.com/docs/manual/core/sharding-reshard-a-collection/) a collection, make a fresh backup and re-enable point-in-time recovery oplog slicing to prevent data inconsistency and restore failure.
 
+    **For MongoDB 8.0 and higher versions**
+
+    If you [unshard a collection :octicons-link-external-16:](https://www.mongodb.com/docs/v8.0/reference/command/unshardCollection/), make a fresh backup and re-enable point-in-time recovery oplog slicing to prevent data inconsistency and restore failure.
+
 Starting with version [2.4.0](../release-notes/2.4.0.md), oplog slicing runs as follows:
 
 * **Logical backups** 
 
-        Before backup starts, the point-in-time recovery routine is automatically disabled. A backup routine creates oplog slices during the backup creation. After the backup is complete, the point-in-time recovery routine is re-enabled automatically. It copies the slices taken during the backup and continues oplog slicing from the latest timestamp. 
+    Before backup starts, the point-in-time recovery routine is automatically disabled. A backup routine creates oplog slices during the backup creation. After the backup is complete, the point-in-time recovery routine is re-enabled automatically. It copies the slices taken during the backup and continues oplog slicing from the latest timestamp. 
 
 * **Physical backups** 
 

docs/features/selective-backup.md

@@ -25,6 +25,7 @@ With the selective backup and restore functionality, you have the following opti
 
 6. System collections in ``admin``, ``config``, and ``local`` databases cannot be backed up and restored selectively. You must make a full backup and restore to include them.
 7. Selective point-in-time recovery is not supported for sharded clusters.
+8. Selective backups are not supported for deployments with [config shards :octicons-link-external-16:](https://www.mongodb.com/docs/v8.0/core/sharded-cluster-config-servers/#std-label-sharded-cluster-config-server-config-shards) - config server replica sets that also store application data.
 
 
 ## Sharded collections

docs/usage/start-backup.md

@@ -153,7 +153,8 @@ The following diagram illustrates the backup flow.
 
 !!! important
 
-    If you reshard a collection in MongoDB 5.0 and higher versions, make a fresh backup to prevent data inconsistency and restore failure.
+    If you reshard a collection in MongoDB 5.0 and higher versions or unshard a collection in MongoDB 8.0 and higher versions, make a fresh backup to prevent data inconsistency and restore failure.
+
 
 ### Adjust node priority for backups