diff --git a/Firestore/samples/V1/FirestoreClient/listen.php b/Firestore/samples/V1/FirestoreClient/listen.php
index 8f76dfc566b..ef83ea1e763 100644
--- a/Firestore/samples/V1/FirestoreClient/listen.php
+++ b/Firestore/samples/V1/FirestoreClient/listen.php
@@ -30,8 +30,8 @@
 use Google\Cloud\Firestore\V1\ListenResponse;
 
 /**
- * Listens to changes. This method is only available via the gRPC API (not
- * REST).
+ * Listens to changes. This method is only available via gRPC or WebChannel
+ * (not REST).
  *
  * @param string $database The database name. In the format:
  *                         `projects/{project_id}/databases/{database_id}`.
diff --git a/Firestore/samples/V1/FirestoreClient/write.php b/Firestore/samples/V1/FirestoreClient/write.php
index a1fc755c6be..b74e8a2651e 100644
--- a/Firestore/samples/V1/FirestoreClient/write.php
+++ b/Firestore/samples/V1/FirestoreClient/write.php
@@ -31,7 +31,7 @@
 
 /**
  * Streams batches of document updates and deletes, in order. This method is
- * only available via the gRPC API (not REST).
+ * only available via gRPC or WebChannel (not REST).
  *
  * @param string $database The database name. In the format:
  *                         `projects/{project_id}/databases/{database_id}`.
diff --git a/Firestore/src/V1/FirestoreGrpcClient.php b/Firestore/src/V1/FirestoreGrpcClient.php
index 8acb9da51e7..8d368d3d396 100644
--- a/Firestore/src/V1/FirestoreGrpcClient.php
+++ b/Firestore/src/V1/FirestoreGrpcClient.php
@@ -225,7 +225,7 @@ public function PartitionQuery(\Google\Cloud\Firestore\V1\PartitionQueryRequest
 
     /**
      * Streams batches of document updates and deletes, in order. This method is
-     * only available via the gRPC API (not REST).
+     * only available via gRPC or WebChannel (not REST).
      * @param array $metadata metadata
      * @param array $options call options
      * @return \Grpc\BidiStreamingCall
@@ -237,8 +237,8 @@ public function Write($metadata = [], $options = []) {
     }
 
     /**
-     * Listens to changes. This method is only available via the gRPC API (not
-     * REST).
+     * Listens to changes. This method is only available via gRPC or WebChannel
+     * (not REST).
      * @param array $metadata metadata
      * @param array $options call options
      * @return \Grpc\BidiStreamingCall
diff --git a/Firestore/src/V1/Gapic/FirestoreGapicClient.php b/Firestore/src/V1/Gapic/FirestoreGapicClient.php
index 6d09dba2574..70b7d6e58ff 100644
--- a/Firestore/src/V1/Gapic/FirestoreGapicClient.php
+++ b/Firestore/src/V1/Gapic/FirestoreGapicClient.php
@@ -828,8 +828,8 @@ public function listDocuments($parent, $collectionId, array $optionalArgs = [])
     }
 
     /**
-     * Listens to changes. This method is only available via the gRPC API (not
-     * REST).
+     * Listens to changes. This method is only available via gRPC or WebChannel
+     * (not REST).
      *
      * Sample code:
      * ```
@@ -1269,7 +1269,7 @@ public function updateDocument($document, $updateMask, array $optionalArgs = [])
 
     /**
      * Streams batches of document updates and deletes, in order. This method is
-     * only available via the gRPC API (not REST).
+     * only available via gRPC or WebChannel (not REST).
      *
      * Sample code:
      * ```
diff --git a/Firestore/src/V1/RunAggregationQueryResponse.php b/Firestore/src/V1/RunAggregationQueryResponse.php
index 421a8bd744d..878f1d28a2a 100644
--- a/Firestore/src/V1/RunAggregationQueryResponse.php
+++ b/Firestore/src/V1/RunAggregationQueryResponse.php
@@ -32,7 +32,13 @@ class RunAggregationQueryResponse extends \Google\Protobuf\Internal\Message
      */
     private $transaction = '';
     /**
-     * The time at which the aggregate value is valid for.
+     * The time at which the aggregate result was computed. This is always
+     * monotonically increasing; in this case, the previous AggregationResult in
+     * the result stream are guaranteed not to have changed between their
+     * `read_time` and this one.
+     * If the query returns no results, a response with `read_time` and no
+     * `result` will be sent, and this represents the time at which the query
+     * was run.
      *
      * Generated from protobuf field <code>.google.protobuf.Timestamp read_time = 3;</code>
      */
@@ -52,7 +58,13 @@ class RunAggregationQueryResponse extends \Google\Protobuf\Internal\Message
      *           Only present on the first response when the request requested to start
      *           a new transaction.
      *     @type \Google\Protobuf\Timestamp $read_time
-     *           The time at which the aggregate value is valid for.
+     *           The time at which the aggregate result was computed. This is always
+     *           monotonically increasing; in this case, the previous AggregationResult in
+     *           the result stream are guaranteed not to have changed between their
+     *           `read_time` and this one.
+     *           If the query returns no results, a response with `read_time` and no
+     *           `result` will be sent, and this represents the time at which the query
+     *           was run.
      * }
      */
     public function __construct($data = NULL) {
@@ -129,7 +141,13 @@ public function setTransaction($var)
     }
 
     /**
-     * The time at which the aggregate value is valid for.
+     * The time at which the aggregate result was computed. This is always
+     * monotonically increasing; in this case, the previous AggregationResult in
+     * the result stream are guaranteed not to have changed between their
+     * `read_time` and this one.
+     * If the query returns no results, a response with `read_time` and no
+     * `result` will be sent, and this represents the time at which the query
+     * was run.
      *
      * Generated from protobuf field <code>.google.protobuf.Timestamp read_time = 3;</code>
      * @return \Google\Protobuf\Timestamp|null
@@ -150,7 +168,13 @@ public function clearReadTime()
     }
 
     /**
-     * The time at which the aggregate value is valid for.
+     * The time at which the aggregate result was computed. This is always
+     * monotonically increasing; in this case, the previous AggregationResult in
+     * the result stream are guaranteed not to have changed between their
+     * `read_time` and this one.
+     * If the query returns no results, a response with `read_time` and no
+     * `result` will be sent, and this represents the time at which the query
+     * was run.
      *
      * Generated from protobuf field <code>.google.protobuf.Timestamp read_time = 3;</code>
      * @param \Google\Protobuf\Timestamp $var
diff --git a/Firestore/src/V1/StructuredAggregationQuery/Aggregation.php b/Firestore/src/V1/StructuredAggregationQuery/Aggregation.php
index 9ea3cab0bed..66fa014226a 100644
--- a/Firestore/src/V1/StructuredAggregationQuery/Aggregation.php
+++ b/Firestore/src/V1/StructuredAggregationQuery/Aggregation.php
@@ -9,7 +9,7 @@
 use Google\Protobuf\Internal\GPBUtil;
 
 /**
- * Defines a aggregation that produces a single result.
+ * Defines an aggregation that produces a single result.
  *
  * Generated from protobuf message <code>google.firestore.v1.StructuredAggregationQuery.Aggregation</code>
  */
@@ -25,7 +25,7 @@ class Aggregation extends \Google\Protobuf\Internal\Message
      *   COUNT_UP_TO(1) AS count_up_to_1,
      *   COUNT_UP_TO(2),
      *   COUNT_UP_TO(3) AS count_up_to_3,
-     *   COUNT_UP_TO(4)
+     *   COUNT(*)
      * OVER (
      *   ...
      * );
@@ -36,7 +36,7 @@ class Aggregation extends \Google\Protobuf\Internal\Message
      *   COUNT_UP_TO(1) AS count_up_to_1,
      *   COUNT_UP_TO(2) AS field_1,
      *   COUNT_UP_TO(3) AS count_up_to_3,
-     *   COUNT_UP_TO(4) AS field_2
+     *   COUNT(*) AS field_2
      * OVER (
      *   ...
      * );
@@ -69,7 +69,7 @@ class Aggregation extends \Google\Protobuf\Internal\Message
      *             COUNT_UP_TO(1) AS count_up_to_1,
      *             COUNT_UP_TO(2),
      *             COUNT_UP_TO(3) AS count_up_to_3,
-     *             COUNT_UP_TO(4)
+     *             COUNT(*)
      *           OVER (
      *             ...
      *           );
@@ -80,7 +80,7 @@ class Aggregation extends \Google\Protobuf\Internal\Message
      *             COUNT_UP_TO(1) AS count_up_to_1,
      *             COUNT_UP_TO(2) AS field_1,
      *             COUNT_UP_TO(3) AS count_up_to_3,
-     *             COUNT_UP_TO(4) AS field_2
+     *             COUNT(*) AS field_2
      *           OVER (
      *             ...
      *           );
@@ -137,7 +137,7 @@ public function setCount($var)
      *   COUNT_UP_TO(1) AS count_up_to_1,
      *   COUNT_UP_TO(2),
      *   COUNT_UP_TO(3) AS count_up_to_3,
-     *   COUNT_UP_TO(4)
+     *   COUNT(*)
      * OVER (
      *   ...
      * );
@@ -148,7 +148,7 @@ public function setCount($var)
      *   COUNT_UP_TO(1) AS count_up_to_1,
      *   COUNT_UP_TO(2) AS field_1,
      *   COUNT_UP_TO(3) AS count_up_to_3,
-     *   COUNT_UP_TO(4) AS field_2
+     *   COUNT(*) AS field_2
      * OVER (
      *   ...
      * );
@@ -176,7 +176,7 @@ public function getAlias()
      *   COUNT_UP_TO(1) AS count_up_to_1,
      *   COUNT_UP_TO(2),
      *   COUNT_UP_TO(3) AS count_up_to_3,
-     *   COUNT_UP_TO(4)
+     *   COUNT(*)
      * OVER (
      *   ...
      * );
@@ -187,7 +187,7 @@ public function getAlias()
      *   COUNT_UP_TO(1) AS count_up_to_1,
      *   COUNT_UP_TO(2) AS field_1,
      *   COUNT_UP_TO(3) AS count_up_to_3,
-     *   COUNT_UP_TO(4) AS field_2
+     *   COUNT(*) AS field_2
      * OVER (
      *   ...
      * );
diff --git a/Firestore/src/V1/StructuredAggregationQuery/Aggregation/Count.php b/Firestore/src/V1/StructuredAggregationQuery/Aggregation/Count.php
index 8fe6852fe54..d677245f938 100644
--- a/Firestore/src/V1/StructuredAggregationQuery/Aggregation/Count.php
+++ b/Firestore/src/V1/StructuredAggregationQuery/Aggregation/Count.php
@@ -21,7 +21,7 @@ class Count extends \Google\Protobuf\Internal\Message
      * Optional. Optional constraint on the maximum number of documents to
      * count.
      * This provides a way to set an upper bound on the number of documents
-     * to scan, limiting latency and cost.
+     * to scan, limiting latency, and cost.
      * Unspecified is interpreted as no bound.
      * High-Level Example:
      * ```
@@ -44,7 +44,7 @@ class Count extends \Google\Protobuf\Internal\Message
      *           Optional. Optional constraint on the maximum number of documents to
      *           count.
      *           This provides a way to set an upper bound on the number of documents
-     *           to scan, limiting latency and cost.
+     *           to scan, limiting latency, and cost.
      *           Unspecified is interpreted as no bound.
      *           High-Level Example:
      *           ```
@@ -63,7 +63,7 @@ public function __construct($data = NULL) {
      * Optional. Optional constraint on the maximum number of documents to
      * count.
      * This provides a way to set an upper bound on the number of documents
-     * to scan, limiting latency and cost.
+     * to scan, limiting latency, and cost.
      * Unspecified is interpreted as no bound.
      * High-Level Example:
      * ```
@@ -96,7 +96,7 @@ public function clearUpTo()
      * Optional. Optional constraint on the maximum number of documents to
      * count.
      * This provides a way to set an upper bound on the number of documents
-     * to scan, limiting latency and cost.
+     * to scan, limiting latency, and cost.
      * Unspecified is interpreted as no bound.
      * High-Level Example:
      * ```
@@ -117,7 +117,7 @@ public function getUpToValue()
      * Optional. Optional constraint on the maximum number of documents to
      * count.
      * This provides a way to set an upper bound on the number of documents
-     * to scan, limiting latency and cost.
+     * to scan, limiting latency, and cost.
      * Unspecified is interpreted as no bound.
      * High-Level Example:
      * ```
@@ -144,7 +144,7 @@ public function setUpTo($var)
      * Optional. Optional constraint on the maximum number of documents to
      * count.
      * This provides a way to set an upper bound on the number of documents
-     * to scan, limiting latency and cost.
+     * to scan, limiting latency, and cost.
      * Unspecified is interpreted as no bound.
      * High-Level Example:
      * ```
diff --git a/Firestore/src/V1/StructuredQuery.php b/Firestore/src/V1/StructuredQuery.php
index 3fe21508257..50d0ae832df 100644
--- a/Firestore/src/V1/StructuredQuery.php
+++ b/Firestore/src/V1/StructuredQuery.php
@@ -16,7 +16,10 @@
 class StructuredQuery extends \Google\Protobuf\Internal\Message
 {
     /**
-     * The projection to return.
+     * Optional sub-set of the fields to return.
+     * This acts as a [DocumentMask][google.firestore.v1.DocumentMask] over the
+     * documents returned from a query. When not set, assumes that the caller
+     * wants all fields returned.
      *
      * Generated from protobuf field <code>.google.firestore.v1.StructuredQuery.Projection select = 1;</code>
      */
@@ -119,7 +122,10 @@ class StructuredQuery extends \Google\Protobuf\Internal\Message
      *     Optional. Data for populating the Message object.
      *
      *     @type \Google\Cloud\Firestore\V1\StructuredQuery\Projection $select
-     *           The projection to return.
+     *           Optional sub-set of the fields to return.
+     *           This acts as a [DocumentMask][google.firestore.v1.DocumentMask] over the
+     *           documents returned from a query. When not set, assumes that the caller
+     *           wants all fields returned.
      *     @type array<\Google\Cloud\Firestore\V1\StructuredQuery\CollectionSelector>|\Google\Protobuf\Internal\RepeatedField $from
      *           The collections to query.
      *     @type \Google\Cloud\Firestore\V1\StructuredQuery\Filter $where
@@ -190,7 +196,10 @@ public function __construct($data = NULL) {
     }
 
     /**
-     * The projection to return.
+     * Optional sub-set of the fields to return.
+     * This acts as a [DocumentMask][google.firestore.v1.DocumentMask] over the
+     * documents returned from a query. When not set, assumes that the caller
+     * wants all fields returned.
      *
      * Generated from protobuf field <code>.google.firestore.v1.StructuredQuery.Projection select = 1;</code>
      * @return \Google\Cloud\Firestore\V1\StructuredQuery\Projection|null
@@ -211,7 +220,10 @@ public function clearSelect()
     }
 
     /**
-     * The projection to return.
+     * Optional sub-set of the fields to return.
+     * This acts as a [DocumentMask][google.firestore.v1.DocumentMask] over the
+     * documents returned from a query. When not set, assumes that the caller
+     * wants all fields returned.
      *
      * Generated from protobuf field <code>.google.firestore.v1.StructuredQuery.Projection select = 1;</code>
      * @param \Google\Cloud\Firestore\V1\StructuredQuery\Projection $var
diff --git a/Firestore/src/V1/StructuredQuery/FieldFilter/Operator.php b/Firestore/src/V1/StructuredQuery/FieldFilter/Operator.php
index 19bf2667796..9721e2039d0 100644
--- a/Firestore/src/V1/StructuredQuery/FieldFilter/Operator.php
+++ b/Firestore/src/V1/StructuredQuery/FieldFilter/Operator.php
@@ -75,8 +75,9 @@ class Operator
     /**
      * The given `field` is equal to at least one value in the given array.
      * Requires:
-     * * That `value` is a non-empty `ArrayValue` with at most 10 values.
-     * * No other `IN` or `ARRAY_CONTAINS_ANY` or `NOT_IN`.
+     * * That `value` is a non-empty `ArrayValue`, subject to disjunction
+     *   limits.
+     * * No `NOT_IN` filters in the same query.
      *
      * Generated from protobuf enum <code>IN = 8;</code>
      */
@@ -85,8 +86,10 @@ class Operator
      * The given `field` is an array that contains any of the values in the
      * given array.
      * Requires:
-     * * That `value` is a non-empty `ArrayValue` with at most 10 values.
-     * * No other `IN` or `ARRAY_CONTAINS_ANY` or `NOT_IN`.
+     * * That `value` is a non-empty `ArrayValue`, subject to disjunction
+     *   limits.
+     * * No other `ARRAY_CONTAINS_ANY` filters within the same disjunction.
+     * * No `NOT_IN` filters in the same query.
      *
      * Generated from protobuf enum <code>ARRAY_CONTAINS_ANY = 9;</code>
      */
@@ -95,7 +98,7 @@ class Operator
      * The value of the `field` is not in the given array.
      * Requires:
      * * That `value` is a non-empty `ArrayValue` with at most 10 values.
-     * * No other `IN`, `ARRAY_CONTAINS_ANY`, `NOT_IN`, `NOT_EQUAL`,
+     * * No other `OR`, `IN`, `ARRAY_CONTAINS_ANY`, `NOT_IN`, `NOT_EQUAL`,
      *   `IS_NOT_NULL`, or `IS_NOT_NAN`.
      * * That `field` comes first in the `order_by`.
      *