Update mongodb-indexing.md

Author: gahl-levy

articles/cosmos-db/mongodb/mongodb-indexing.md

@@ -199,7 +199,8 @@ As an alternative, you could create multiple wildcard indexes.
 
 The following operations are common for accounts serving wire protocol version 4.0 and accounts serving earlier versions. You can learn more about [supported indexes and indexed properties](feature-support-40.md#indexes-and-index-properties).
 
-### Unique indexes
+### 
+indexes
 
 [Unique indexes](../unique-keys.md) are useful for enforcing that two or more documents do not contain the same value for indexed fields.
 
@@ -245,41 +246,6 @@ In the preceding example, omitting the ```"university":1``` clause returns an er
 
 Unique indexes need to be created while the collection is empty. 
 
-Support for unique index on existing collections with data is available in preview for accounts that do not use Synapse Link or Continuous backup. You can sign up for the feature “Azure Cosmos DB API for MongoDB New Unique Indexes in existing collection” through the [Preview Features blade in the portal](./../access-previews.md). 
-
-#### Unique partial indexes
-
-Unique partial indexes can be created by specifying a partialFilterExpression along with the 'unique' constraint in the index. This results in the unique constraint being applied only to the documents that meet the specified filter expression.
-
-The unique constraint will not be effective for documents that do not meet the specified criteria. As a result, other documents will not be prevented from being inserted into the collection.
-
-This feature is supported with the Cosmos DB API for MongoDB versions 3.6 and above.
-
-To create a unique partial index from Mongo Shell, use the command `db.collection.createIndex()` with the 'partialFilterExpression' option and 'unique' constraint.
-The partialFilterExpression option accepts a json document that specifies the filter condition using:
-
-* equality expressions (i.e. field: value or using the $eq operator),
-*'$exists: true' expression,
-* $gt, $gte, $lt, $lte expressions,
-* $type expressions,
-* $and operator at the top-level only
-
-The following command creates an index on collection `books` that specifies a unique constraint on the `title` field and a partial filter expression `rating: { $gte: 3 }`:
-
-```shell
-db.books.createIndex( 
-   { title: 1 }, 
-   { unique: true, partialFilterExpression: { rating: { $gte: 3 } } } 
-) 
-```
-
-To delete a partial unique index using from Mongo Shell, use the command `getIndexes()` to list the indexes in the collection.
-Then drop the index with the following command:
-
-```shell
-db.books.dropIndex("indexName")
-```
-
 ### TTL indexes
 
 To enable document expiration in a particular collection, you need to create a [time-to-live (TTL) index](../time-to-live.md). A TTL index is an index on the `_ts` field with an `expireAfterSeconds` value.