diff --git a/build/Common.nonprod.props b/build/Common.nonprod.props
index 4ef53e18789..0738072ce6a 100644
--- a/build/Common.nonprod.props
+++ b/build/Common.nonprod.props
@@ -38,7 +38,7 @@
     <MicrosoftExtensionsLoggingPkgVer>[5.0.0,6.0)</MicrosoftExtensionsLoggingPkgVer>
     <MicrosoftExtensionsLoggingAbstractionsPkgVer>[5.0.0,6.0)</MicrosoftExtensionsLoggingAbstractionsPkgVer>
     <MicrosoftExtensionsLoggingConsolePkgVer>[5.0.0,6.0)</MicrosoftExtensionsLoggingConsolePkgVer>
-    <MicrosoftNETTestSdkPkgVer>[16.9.1]</MicrosoftNETTestSdkPkgVer>
+    <MicrosoftNETTestSdkPkgVer>[16.10.0]</MicrosoftNETTestSdkPkgVer>
     <MoqPkgVer>[4.14.5,5.0)</MoqPkgVer>
     <RabbitMQClientPkgVer>[6.1.0,7.0)</RabbitMQClientPkgVer>
     <StackExchangeRedisPkgVer>[2.1.58,3.0)</StackExchangeRedisPkgVer>
diff --git a/build/Common.props b/build/Common.props
index 9282722fa74..5ba16ffbe7d 100644
--- a/build/Common.props
+++ b/build/Common.props
@@ -30,7 +30,7 @@
     <MicrosoftAspNetCoreHttpFeaturesPkgVer>[2.1.1,6.0)</MicrosoftAspNetCoreHttpFeaturesPkgVer>
     <MicrosoftAspNetTelemetryCorrelationPkgVer>[1.0.7,2.0)</MicrosoftAspNetTelemetryCorrelationPkgVer>
     <MicrosoftCodeAnalysisAnalyzersPkgVer>[3.3.1]</MicrosoftCodeAnalysisAnalyzersPkgVer>
-    <MicrosoftCodeCoveragePkgVer>[16.9.1]</MicrosoftCodeCoveragePkgVer>
+    <MicrosoftCodeCoveragePkgVer>[16.10.0]</MicrosoftCodeCoveragePkgVer>
     <MicrosoftExtensionsHostingAbstractionsPkgVer>[2.1.0,6.0)</MicrosoftExtensionsHostingAbstractionsPkgVer>
     <MicrosoftExtensionsLoggingPkgVer>[2.1.0,6.0)</MicrosoftExtensionsLoggingPkgVer>
     <MicrosoftExtensionsLoggingConfigurationPkgVer>[2.1.0,6.0)</MicrosoftExtensionsLoggingConfigurationPkgVer>
@@ -57,6 +57,7 @@
     <PackageReference Include="StyleCop.Analyzers" Version="$(StyleCopAnalyzersPkgVer)" Condition="'$(SkipAnalysis)'!='true'">
       <PrivateAssets>All</PrivateAssets>
     </PackageReference>
+    <!--When updating the Microsoft.CodeCoverage package, update the version number in .\build\process-codecoverage.ps1 as well-->
     <PackageReference Include="Microsoft.CodeCoverage" Version="$(MicrosoftCodeCoveragePkgVer)" Condition="'$(Configuration)'=='Release'"/>
     <!--<PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="$(MicrosoftCodeAnalysisAnalyzersPkgVer)" Condition="'$(SkipAnalysis)'!='true'">
       <PrivateAssets>all</PrivateAssets>
diff --git a/build/process-codecoverage.ps1 b/build/process-codecoverage.ps1
index 10cac6035be..179f296e4fb 100644
--- a/build/process-codecoverage.ps1
+++ b/build/process-codecoverage.ps1
@@ -2,7 +2,7 @@
 Write-Host $env:USERPROFILE
 foreach ($file in $files)
 {
-    $command = $env:USERPROFILE+ '\.nuget\packages\microsoft.codecoverage\16.9.1\build\netstandard1.0\CodeCoverage\CodeCoverage.exe analyze /output:' + $file.DirectoryName + '\' + $file.Name + '.xml '+ $file.FullName
+    $command = $env:USERPROFILE+ '\.nuget\packages\microsoft.codecoverage\16.10.0\build\netstandard1.0\CodeCoverage\CodeCoverage.exe analyze /output:' + $file.DirectoryName + '\' + $file.Name + '.xml '+ $file.FullName
     Write-Host $command
     Invoke-Expression $command
 }
diff --git a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/collector/trace/v1/trace_service.proto b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/collector/trace/v1/trace_service.proto
index 37d0237254e..e889a390540 100644
--- a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/collector/trace/v1/trace_service.proto
+++ b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/collector/trace/v1/trace_service.proto
@@ -24,7 +24,7 @@ option java_outer_classname = "TraceServiceProto";
 option go_package = "github.com/open-telemetry/opentelemetry-proto/gen/go/collector/trace/v1";
 
 // Service that can be used to push spans between one Application instrumented with
-// OpenTelemetry and an collector, or between an collector and a central collector (in this
+// OpenTelemetry and a collector, or between a collector and a central collector (in this
 // case spans are sent/received to/from multiple Applications).
 service TraceService {
   // For performance reasons, it is recommended to keep this RPC
diff --git a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/common/v1/common.proto b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/common/v1/common.proto
index 214c2182358..8dc24567f5c 100644
--- a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/common/v1/common.proto
+++ b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/common/v1/common.proto
@@ -34,6 +34,7 @@ message AnyValue {
     double double_value = 4;
     ArrayValue array_value = 5;
     KeyValueList kvlist_value = 6;
+    bytes bytes_value = 7;
   }
 }
 
@@ -65,6 +66,8 @@ message KeyValue {
 // StringKeyValue is a pair of key/value strings. This is the simpler (and faster) version
 // of KeyValue that only supports string values.
 message StringKeyValue {
+  option deprecated = true;
+
   string key = 1;
   string value = 2;
 }
diff --git a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/logs/v1/logs.proto b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/logs/v1/logs.proto
index 7e576ba166c..84fafef221b 100644
--- a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/logs/v1/logs.proto
+++ b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/logs/v1/logs.proto
@@ -32,6 +32,11 @@ message ResourceLogs {
 
   // A list of InstrumentationLibraryLogs that originate from a resource.
   repeated InstrumentationLibraryLogs instrumentation_library_logs = 2;
+
+  // This schema_url applies to the data in the "resource" field. It does not apply
+  // to the data in the "instrumentation_library_logs" field which have their own
+  // schema_url field.
+  string schema_url = 3;
 }
 
 // A collection of Logs produced by an InstrumentationLibrary.
@@ -43,6 +48,9 @@ message InstrumentationLibraryLogs {
 
   // A list of log records.
   repeated LogRecord logs = 2;
+
+  // This schema_url applies to all logs in the "logs" field.
+  string schema_url = 3;
 }
 
 // Possible values for LogRecord.SeverityNumber.
@@ -82,7 +90,7 @@ enum LogRecordFlags {
 }
 
 // A log record according to OpenTelemetry Log Data Model:
-// https://github.com/open-telemetry/oteps/blob/master/text/logs/0097-log-data-model.md
+// https://github.com/open-telemetry/oteps/blob/main/text/logs/0097-log-data-model.md
 message LogRecord {
   // time_unix_nano is the time when the event occurred.
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January 1970.
diff --git a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/experimental/metrics_config_service.proto b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/experimental/metrics_config_service.proto
new file mode 100644
index 00000000000..d73a7fee804
--- /dev/null
+++ b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/experimental/metrics_config_service.proto
@@ -0,0 +1,102 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package opentelemetry.proto.metrics.experimental;
+
+import "opentelemetry/proto/resource/v1/resource.proto";
+
+option java_multiple_files = true;
+option java_package = "io.opentelemetry.proto.metrics.experimental";
+option java_outer_classname = "MetricConfigServiceProto";
+option go_package = "github.com/open-telemetry/opentelemetry-proto/gen/go/metrics/experimental";
+
+// MetricConfig is a service that enables updating metric schedules, trace
+// parameters, and other configurations on the SDK without having to restart the
+// instrumented application. The collector can also serve as the configuration
+// service, acting as a bridge between third-party configuration services and
+// the SDK, piping updated configs from a third-party source to an instrumented
+// application.
+service MetricConfig {
+  rpc GetMetricConfig (MetricConfigRequest) returns (MetricConfigResponse);
+}
+
+message MetricConfigRequest{
+
+  // Required. The resource for which configuration should be returned.
+  opentelemetry.proto.resource.v1.Resource resource = 1;
+
+  // Optional. The value of MetricConfigResponse.fingerprint for the last
+  // configuration that the caller received and successfully applied.
+  bytes last_known_fingerprint = 2;
+}
+
+message MetricConfigResponse {
+
+  // Optional. The fingerprint associated with this MetricConfigResponse. Each
+  // change in configs yields a different fingerprint. The resource SHOULD copy
+  // this value to MetricConfigRequest.last_known_fingerprint for the next
+  // configuration request. If there are no changes between fingerprint and
+  // MetricConfigRequest.last_known_fingerprint, then all other fields besides
+  // fingerprint in the response are optional, or the same as the last update if
+  // present.
+  //
+  // The exact mechanics of generating the fingerprint is up to the
+  // implementation. However, a fingerprint must be deterministically determined
+  // by the configurations -- the same configuration will generate the same
+  // fingerprint on any instance of an implementation. Hence using a timestamp is
+  // unacceptable, but a deterministic hash is fine.
+  bytes fingerprint = 1;
+
+  // A Schedule is used to apply a particular scheduling configuration to
+  // a metric. If a metric name matches a schedule's patterns, then the metric
+  // adopts the configuration specified by the schedule.
+  message Schedule {
+
+    // A light-weight pattern that can match 1 or more
+    // metrics, for which this schedule will apply. The string is used to
+    // match against metric names. It should not exceed 100k characters.
+    message Pattern {
+      oneof match {
+        string equal_to = 1;       // matches the metric name exactly
+        string starts_with = 2;  // prefix-matches the metric name
+      }
+    }
+
+    // Metrics with names that match a rule in the inclusion_patterns are
+    // targeted by this schedule. Metrics that match the exclusion_patterns
+    // are not targeted for this schedule, even if they match an inclusion
+    // pattern.
+    repeated Pattern exclusion_patterns = 1;
+    repeated Pattern inclusion_patterns = 2;
+
+    // Describes the collection period for each metric in seconds.
+    // A period of 0 means to not export.
+    int32 period_sec = 3;
+  }
+
+  // A single metric may match multiple schedules. In such cases, the schedule
+  // that specifies the smallest period is applied.
+  //
+  // Note, for optimization purposes, it is recommended to use as few schedules
+  // as possible to capture all required metric updates. Where you can be
+  // conservative, do take full advantage of the inclusion/exclusion patterns to
+  // capture as much of your targeted metrics.
+  repeated Schedule schedules = 2;
+
+  // Optional. The client is suggested to wait this long (in seconds) before
+  // pinging the configuration service again.
+  int32 suggested_wait_time_sec = 3;
+}
diff --git a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/v1/metrics.proto b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/v1/metrics.proto
index 371a43ceecd..244f4229bda 100644
--- a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/v1/metrics.proto
+++ b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/metrics/v1/metrics.proto
@@ -32,6 +32,11 @@ message ResourceMetrics {
 
   // A list of metrics that originate from a resource.
   repeated InstrumentationLibraryMetrics instrumentation_library_metrics = 2;
+
+  // This schema_url applies to the data in the "resource" field. It does not apply
+  // to the data in the "instrumentation_library_metrics" field which have their own
+  // schema_url field.
+  string schema_url = 3;
 }
 
 // A collection of Metrics produced by an InstrumentationLibrary.
@@ -43,9 +48,16 @@ message InstrumentationLibraryMetrics {
 
   // A list of metrics that originate from an instrumentation library.
   repeated Metric metrics = 2;
+
+  // This schema_url applies to all metrics in the "metrics" field.
+  string schema_url = 3;
 }
 
-// Defines a Metric which has one or more timeseries.
+// Defines a Metric which has one or more timeseries.  The following is a
+// brief summary of the Metric data model.  For more details, see:
+//
+//   https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/datamodel.md
+//
 //
 // The data model and relation between entities is shown in the
 // diagram below. Here, "DataPoint" is the term used to refer to any
@@ -54,8 +66,8 @@ message InstrumentationLibraryMetrics {
 //
 // - Metric is composed of a metadata and data.
 // - Metadata part contains a name, description, unit.
-// - Data is one of the possible types (Gauge, Sum, Histogram, etc.).
-// - DataPoint contains timestamps, labels, and one of the possible value type
+// - Data is one of the possible types (Sum, Gauge, Histogram, Summary).
+// - DataPoint contains timestamps, attributes, and one of the possible value type
 //   fields.
 //
 //     Metric
@@ -95,14 +107,37 @@ message InstrumentationLibraryMetrics {
 //                        |+-----+                    |
 //                        +---------------------------+
 //
+// Each distinct type of DataPoint represents the output of a specific
+// aggregation function, the result of applying the DataPoint's
+// associated function of to one or more measurements.
+//
 // All DataPoint types have three common fields:
-// - Labels zero or more key-value pairs associated with the data point.
-// - StartTimeUnixNano MUST be set to the start of the interval when the data's
-//   type includes an AggregationTemporality. This field is not set otherwise.
-// - TimeUnixNano MUST be set to:
-//   - the moment when an aggregation is reported (independent of the
-//     aggregation temporality).
-//   - the instantaneous time of the event.
+// - Attributes includes key-value pairs associated with the data point
+// - TimeUnixNano is required, set to the end time of the aggregation
+// - StartTimeUnixNano is optional, but strongly encouraged for DataPoints
+//   having an AggregationTemporality field, as discussed below.
+//
+// Both TimeUnixNano and StartTimeUnixNano values are expressed as
+// UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January 1970.
+//
+// # TimeUnixNano
+//
+// This field is required, having consistent interpretation across
+// DataPoint types.  TimeUnixNano is the moment corresponding to when
+// the data point's aggregate value was captured.
+//
+// Data points with the 0 value for TimeUnixNano SHOULD be rejected
+// by consumers.
+//
+// # StartTimeUnixNano
+//
+// StartTimeUnixNano in general allows detecting when a sequence of
+// observations is unbroken.  This field indicates to consumers the
+// start time for points with cumulative and delta
+// AggregationTemporality, and it should be included whenever possible
+// to support correct rate calculation.  Although it may be omitted
+// when the start time is truly unknown, setting StartTimeUnixNano is
+// strongly encouraged.
 message Metric {
   // name of the metric, including its DNS name prefix. It must be unique.
   string name = 1;
@@ -114,68 +149,74 @@ message Metric {
   // described by http://unitsofmeasure.org/ucum.html.
   string unit = 3;
 
-  // TODO: Decide if support for RawMeasurements (measurements recorded using
-  // the synchronous instruments) is necessary. It can be used to delegate the
-  // aggregation from the application to the agent/collector. See
-  // https://github.com/open-telemetry/opentelemetry-specification/issues/617
-
   // Data determines the aggregation type (if any) of the metric, what is the
   // reported value type for the data points, as well as the relatationship to
   // the time interval over which they are reported.
-  //
-  // TODO: Update table after the decision on:
-  // https://github.com/open-telemetry/opentelemetry-specification/issues/731.
-  // By default, metrics recording using the OpenTelemetry API are exported as
-  // (the table does not include MeasurementValueType to avoid extra rows):
-  //
-  //   Instrument         Type
-  //   ----------------------------------------------
-  //   Counter            Sum(aggregation_temporality=delta;is_monotonic=true)
-  //   UpDownCounter      Sum(aggregation_temporality=delta;is_monotonic=false)
-  //   ValueRecorder      TBD
-  //   SumObserver        Sum(aggregation_temporality=cumulative;is_monotonic=true)
-  //   UpDownSumObserver  Sum(aggregation_temporality=cumulative;is_monotonic=false)
-  //   ValueObserver      Gauge()
   oneof data {
-    IntGauge int_gauge = 4;
-    DoubleGauge double_gauge = 5;
-    IntSum int_sum = 6;
-    DoubleSum double_sum = 7;
-    IntHistogram int_histogram = 8;
-    DoubleHistogram double_histogram = 9;
-    DoubleSummary double_summary = 11;
+    // IntGauge and IntSum are deprecated and will be removed soon.
+    // 1. Old senders and receivers that are not aware of this change will
+    // continue using the `int_gauge` and `int_sum` fields.
+    // 2. New senders, which are aware of this change MUST send only `gauge`
+    // and `sum` fields.
+    // 3. New receivers, which are aware of this change MUST convert these into
+    // `gauge` and `sum` by using the provided as_int field in the oneof values.
+    // This field will be removed in ~3 months, on July 1, 2021.
+    IntGauge int_gauge = 4 [deprecated = true];
+    Gauge gauge = 5;
+    // This field will be removed in ~3 months, on July 1, 2021.
+    IntSum int_sum = 6 [deprecated = true];
+    Sum sum = 7;
+
+    // IntHistogram is deprecated and will be removed soon.
+    // 1. Old senders and receivers that are not aware of this change will
+    // continue using the `int_histogram` field.
+    // 2. New senders, which are aware of this change MUST send only `histogram`.
+    // 3. New receivers, which are aware of this change MUST convert this into
+    // `histogram` by simply converting all int64 values into float.
+    // This field will be removed in ~3 months, on July 1, 2021.
+    IntHistogram int_histogram = 8 [deprecated = true];
+    Histogram histogram = 9;
+    Summary summary = 11;
   }
 }
 
-// Gauge represents the type of a int scalar metric that always exports the
+// IntGauge is deprecated.  Use Gauge with an integer value in NumberDataPoint.
+//
+// IntGauge represents the type of a int scalar metric that always exports the
 // "current value" for every data point. It should be used for an "unknown"
 // aggregation.
-// 
+//
 // A Gauge does not support different aggregation temporalities. Given the
 // aggregation is unknown, points cannot be combined using the same
 // aggregation, regardless of aggregation temporalities. Therefore,
 // AggregationTemporality is not included. Consequently, this also means
 // "StartTimeUnixNano" is ignored for all data points.
 message IntGauge {
+  option deprecated = true;
+
   repeated IntDataPoint data_points = 1;
 }
 
 // Gauge represents the type of a double scalar metric that always exports the
 // "current value" for every data point. It should be used for an "unknown"
 // aggregation.
-// 
+//
 // A Gauge does not support different aggregation temporalities. Given the
 // aggregation is unknown, points cannot be combined using the same
 // aggregation, regardless of aggregation temporalities. Therefore,
 // AggregationTemporality is not included. Consequently, this also means
 // "StartTimeUnixNano" is ignored for all data points.
-message DoubleGauge {
-  repeated DoubleDataPoint data_points = 1;
+message Gauge {
+  repeated NumberDataPoint data_points = 1;
 }
 
-// Sum represents the type of a numeric int scalar metric that is calculated as
+// IntSum is deprecated.  Use Sum with an integer value in NumberDataPoint.
+//
+// IntSum represents the type of a numeric int scalar metric that is calculated as
 // a sum of all reported measurements over a time interval.
 message IntSum {
+  option deprecated = true;
+
   repeated IntDataPoint data_points = 1;
 
   // aggregation_temporality describes if the aggregator reports delta changes
@@ -188,9 +229,9 @@ message IntSum {
 
 // Sum represents the type of a numeric double scalar metric that is calculated
 // as a sum of all reported measurements over a time interval.
-message DoubleSum {
-  repeated DoubleDataPoint data_points = 1;
-  
+message Sum {
+  repeated NumberDataPoint data_points = 1;
+
   // aggregation_temporality describes if the aggregator reports delta changes
   // since last report time, or cumulative changes since a fixed start time.
   AggregationTemporality aggregation_temporality = 2;
@@ -199,9 +240,14 @@ message DoubleSum {
   bool is_monotonic = 3;
 }
 
-// Represents the type of a metric that is calculated by aggregating as a
+// IntHistogram is deprecated, replaced by Histogram points using double-
+// valued exemplars.
+//
+// This represents the type of a metric that is calculated by aggregating as a
 // Histogram of all reported int measurements over a time interval.
 message IntHistogram {
+  option deprecated = true;
+
   repeated IntHistogramDataPoint data_points = 1;
 
   // aggregation_temporality describes if the aggregator reports delta changes
@@ -209,24 +255,24 @@ message IntHistogram {
   AggregationTemporality aggregation_temporality = 2;
 }
 
-// Represents the type of a metric that is calculated by aggregating as a
-// Histogram of all reported double measurements over a time interval.
-message DoubleHistogram {
-  repeated DoubleHistogramDataPoint data_points = 1;
+// Histogram represents the type of a metric that is calculated by aggregating
+// as a Histogram of all reported double measurements over a time interval.
+message Histogram {
+  repeated HistogramDataPoint data_points = 1;
 
   // aggregation_temporality describes if the aggregator reports delta changes
   // since last report time, or cumulative changes since a fixed start time.
   AggregationTemporality aggregation_temporality = 2;
 }
 
-// DoubleSummary metric data are used to convey quantile summaries,
+// Summary metric data are used to convey quantile summaries,
 // a Prometheus (see: https://prometheus.io/docs/concepts/metric_types/#summary)
 // and OpenMetrics (see: https://github.com/OpenObservability/OpenMetrics/blob/4dbf6075567ab43296eed941037c12951faafb92/protos/prometheus.proto#L45)
 // data type. These data points cannot always be merged in a meaningful way.
 // While they can be useful in some applications, histogram data points are
 // recommended for new applications.
-message DoubleSummary {
-  repeated DoubleSummaryDataPoint data_points = 1;
+message Summary {
+  repeated SummaryDataPoint data_points = 1;
 }
 
 // AggregationTemporality defines how a metric aggregator reports aggregated
@@ -293,7 +339,7 @@ enum AggregationTemporality {
   //      number of requests received over the interval of time t_1 to
   //      t_0+1 with a value of 1.
   //
-  // Note: Even though, when reporting changes since last report time, using 
+  // Note: Even though, when reporting changes since last report time, using
   // CUMULATIVE is valid, it is not recommended. This may cause problems for
   // systems that do not use start_time to determine when the aggregation
   // value was reset (e.g. Prometheus).
@@ -303,25 +349,20 @@ enum AggregationTemporality {
 // IntDataPoint is a single data point in a timeseries that describes the
 // time-varying values of a int64 metric.
 message IntDataPoint {
+  option deprecated = true;
+
   // The set of labels that uniquely identify this timeseries.
   repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1;
 
-  // start_time_unix_nano is the last time when the aggregation value was reset
-  // to "zero". For some metric types this is ignored, see data types for more
-  // details.
+  // StartTimeUnixNano is optional but strongly encouraged, see the
+  // the detiled comments above Metric.
   //
-  // The aggregation value is over the time interval (start_time_unix_nano,
-  // time_unix_nano].
-  // 
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
-  //
-  // Value of 0 indicates that the timestamp is unspecified. In that case the
-  // timestamp may be decided by the backend.
   fixed64 start_time_unix_nano = 2;
 
-  // time_unix_nano is the moment when this aggregation value was reported.
-  // 
+  // TimeUnixNano is required, see the detailed comments above Metric.
+  //
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
   fixed64 time_unix_nano = 3;
@@ -334,64 +375,75 @@ message IntDataPoint {
   repeated IntExemplar exemplars = 5;
 }
 
-// DoubleDataPoint is a single data point in a timeseries that describes the
+// NumberDataPoint is a single data point in a timeseries that describes the
 // time-varying value of a double metric.
-message DoubleDataPoint {
-  // The set of labels that uniquely identify this timeseries.
-  repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1;
+message NumberDataPoint {
+  // The set of key/value pairs that uniquely identify the timeseries from
+  // where this point belongs. The list may be empty (may contain 0 elements).
+  repeated opentelemetry.proto.common.v1.KeyValue attributes = 7;
 
-  // start_time_unix_nano is the last time when the aggregation value was reset
-  // to "zero". For some metric types this is ignored, see data types for more
-  // details.
+  // Labels is deprecated and will be removed soon.
+  // 1. Old senders and receivers that are not aware of this change will
+  // continue using the `labels` field.
+  // 2. New senders, which are aware of this change MUST send only `attributes`.
+  // 3. New receivers, which are aware of this change MUST convert this into
+  // `labels` by simply converting all int64 values into float.
+  //
+  // This field will be removed in ~3 months, on July 1, 2021.
+  repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1 [deprecated = true];
+
+  // StartTimeUnixNano is optional but strongly encouraged, see the
+  // the detiled comments above Metric.
   //
-  // The aggregation value is over the time interval (start_time_unix_nano,
-  // time_unix_nano].
-  // 
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
-  //
-  // Value of 0 indicates that the timestamp is unspecified. In that case the
-  // timestamp may be decided by the backend.
   fixed64 start_time_unix_nano = 2;
 
-  // time_unix_nano is the moment when this aggregation value was reported.
-  // 
+  // TimeUnixNano is required, see the detailed comments above Metric.
+  //
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
   fixed64 time_unix_nano = 3;
 
-  // value itself.
-  double value = 4;
+  // The value itself.  A point is considered invalid when one of the recognized
+  // value fields is not present inside this oneof.
+  oneof value {
+    double as_double = 4;
+    sfixed64 as_int = 6;
+  }
 
   // (Optional) List of exemplars collected from
   // measurements that were used to form the data point
-  repeated DoubleExemplar exemplars = 5;
+  repeated Exemplar exemplars = 5;
 }
 
-// IntHistogramDataPoint is a single data point in a timeseries that describes
+// IntHistogramDataPoint is deprecated; use HistogramDataPoint.
+//
+// This is a single data point in a timeseries that describes
 // the time-varying values of a Histogram of int values. A Histogram contains
 // summary statistics for a population of values, it may optionally contain
 // the distribution of those values across a set of buckets.
+//
+// If the histogram contains the distribution of values, then both
+// "explicit_bounds" and "bucket counts" fields must be defined.
+// If the histogram does not contain the distribution of values, then both
+// "explicit_bounds" and "bucket_counts" must be omitted and only "count" and
+// "sum" are known.
 message IntHistogramDataPoint {
+  option deprecated = true;
+
   // The set of labels that uniquely identify this timeseries.
   repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1;
 
-  // start_time_unix_nano is the last time when the aggregation value was reset
-  // to "zero". For some metric types this is ignored, see data types for more
-  // details.
+  // StartTimeUnixNano is optional but strongly encouraged, see the
+  // the detiled comments above Metric.
   //
-  // The aggregation value is over the time interval (start_time_unix_nano,
-  // time_unix_nano].
-  // 
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
-  //
-  // Value of 0 indicates that the timestamp is unspecified. In that case the
-  // timestamp may be decided by the backend.
   fixed64 start_time_unix_nano = 2;
 
-  // time_unix_nano is the moment when this aggregation value was reported.
-  // 
+  // TimeUnixNano is required, see the detailed comments above Metric.
+  //
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
   fixed64 time_unix_nano = 3;
@@ -415,28 +467,20 @@ message IntHistogramDataPoint {
   // the number of elements in explicit_bounds array.
   repeated fixed64 bucket_counts = 6;
 
-  // A histogram may optionally contain the distribution of the values in the population.
-  // In that case one of the option fields below and "buckets" field both must be defined.
-  // Otherwise all option fields and "buckets" field must be omitted in which case the
-  // distribution of values in the histogram is unknown and only the total count and sum are known.
-
-  // explicit_bounds is the only supported bucket option currently.
-  // TODO: Add more bucket options.
-
   // explicit_bounds specifies buckets with explicitly defined bounds for values.
-  // The bucket boundaries are described by "bounds" field.
   //
-  // This defines size(bounds) + 1 (= N) buckets. The boundaries for bucket
-  // at index i are:
+  // This defines size(explicit_bounds) + 1 (= N) buckets. The boundaries for
+  // bucket at index i are:
+  //
+  // (-infinity, explicit_bounds[i]] for i == 0
+  // (explicit_bounds[i-1], explicit_bounds[i]] for 0 < i < N-1
+  // (explicit_bounds[i], +infinity) for i == N-1
   //
-  // (-infinity, bounds[i]) for i == 0
-  // [bounds[i-1], bounds[i]) for 0 < i < N-1
-  // [bounds[i], +infinity) for i == N-1
-  // The values in bounds array must be strictly increasing.
+  // The values in the explicit_bounds array must be strictly increasing.
   //
-  // Note: only [a, b) intervals are currently supported for each bucket except the first one.
-  // If we decide to also support (a, b] intervals we should add support for these by defining
-  // a boolean value which decides what type of intervals to use.
+  // Histogram buckets are inclusive of their upper boundary, except the last
+  // bucket where the boundary is at infinity. This format is intentionally
+  // compatible with the OpenMetrics histogram definition.
   repeated double explicit_bounds = 7;
 
   // (Optional) List of exemplars collected from
@@ -448,26 +492,36 @@ message IntHistogramDataPoint {
 // time-varying values of a Histogram of double values. A Histogram contains
 // summary statistics for a population of values, it may optionally contain the
 // distribution of those values across a set of buckets.
-message DoubleHistogramDataPoint {
-  // The set of labels that uniquely identify this timeseries.
-  repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1;
-
-  // start_time_unix_nano is the last time when the aggregation value was reset
-  // to "zero". For some metric types this is ignored, see data types for more
-  // details.
+//
+// If the histogram contains the distribution of values, then both
+// "explicit_bounds" and "bucket counts" fields must be defined.
+// If the histogram does not contain the distribution of values, then both
+// "explicit_bounds" and "bucket_counts" must be omitted and only "count" and
+// "sum" are known.
+message HistogramDataPoint {
+  // The set of key/value pairs that uniquely identify the timeseries from
+  // where this point belongs. The list may be empty (may contain 0 elements).
+  repeated opentelemetry.proto.common.v1.KeyValue attributes = 9;
+
+  // Labels is deprecated and will be removed soon.
+  // 1. Old senders and receivers that are not aware of this change will
+  // continue using the `labels` field.
+  // 2. New senders, which are aware of this change MUST send only `attributes`.
+  // 3. New receivers, which are aware of this change MUST convert this into
+  // `labels` by simply converting all int64 values into float.
+  //
+  // This field will be removed in ~3 months, on July 1, 2021.
+  repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1 [deprecated = true];
+
+  // StartTimeUnixNano is optional but strongly encouraged, see the
+  // the detiled comments above Metric.
   //
-  // The aggregation value is over the time interval (start_time_unix_nano,
-  // time_unix_nano].
-  // 
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
-  //
-  // Value of 0 indicates that the timestamp is unspecified. In that case the
-  // timestamp may be decided by the backend.
   fixed64 start_time_unix_nano = 2;
 
-  // time_unix_nano is the moment when this aggregation value was reported.
-  // 
+  // TimeUnixNano is required, see the detailed comments above Metric.
+  //
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
   fixed64 time_unix_nano = 3;
@@ -480,6 +534,12 @@ message DoubleHistogramDataPoint {
   // sum of the values in the population. If count is zero then this field
   // must be zero. This value must be equal to the sum of the "sum" fields in
   // buckets if a histogram is provided.
+  //
+  // Note: Sum should only be filled out when measuring non-negative discrete
+  // events, and is assumed to be monotonic over the values of these events.
+  // Negative events *can* be recorded, but sum should not be filled out when
+  // doing so.  This is specifically to enforce compatibility w/ OpenMetrics,
+  // see: https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#histogram
   double sum = 5;
 
   // bucket_counts is an optional field contains the count values of histogram
@@ -491,56 +551,52 @@ message DoubleHistogramDataPoint {
   // the number of elements in explicit_bounds array.
   repeated fixed64 bucket_counts = 6;
 
-  // A histogram may optionally contain the distribution of the values in the population.
-  // In that case one of the option fields below and "buckets" field both must be defined.
-  // Otherwise all option fields and "buckets" field must be omitted in which case the
-  // distribution of values in the histogram is unknown and only the total count and sum are known.
-
-  // explicit_bounds is the only supported bucket option currently.
-  // TODO: Add more bucket options.
-
   // explicit_bounds specifies buckets with explicitly defined bounds for values.
-  // The bucket boundaries are described by "bounds" field.
   //
-  // This defines size(bounds) + 1 (= N) buckets. The boundaries for bucket
-  // at index i are:
+  // This defines size(explicit_bounds) + 1 (= N) buckets. The boundaries for
+  // bucket at index i are:
+  //
+  // (-infinity, explicit_bounds[i]] for i == 0
+  // (explicit_bounds[i-1], explicit_bounds[i]] for 0 < i < N-1
+  // (explicit_bounds[i], +infinity) for i == N-1
   //
-  // (-infinity, bounds[i]) for i == 0
-  // [bounds[i-1], bounds[i]) for 0 < i < N-1
-  // [bounds[i], +infinity) for i == N-1
-  // The values in bounds array must be strictly increasing.
+  // The values in the explicit_bounds array must be strictly increasing.
   //
-  // Note: only [a, b) intervals are currently supported for each bucket except the first one.
-  // If we decide to also support (a, b] intervals we should add support for these by defining
-  // a boolean value which decides what type of intervals to use.
+  // Histogram buckets are inclusive of their upper boundary, except the last
+  // bucket where the boundary is at infinity. This format is intentionally
+  // compatible with the OpenMetrics histogram definition.
   repeated double explicit_bounds = 7;
 
   // (Optional) List of exemplars collected from
   // measurements that were used to form the data point
-  repeated DoubleExemplar exemplars = 8;
+  repeated Exemplar exemplars = 8;
 }
 
-// DoubleSummaryDataPoint is a single data point in a timeseries that describes the
+// SummaryDataPoint is a single data point in a timeseries that describes the
 // time-varying values of a Summary metric.
-message DoubleSummaryDataPoint {
-  // The set of labels that uniquely identify this timeseries.
-  repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1;
+message SummaryDataPoint {
+  // The set of key/value pairs that uniquely identify the timeseries from
+  // where this point belongs. The list may be empty (may contain 0 elements).
+  repeated opentelemetry.proto.common.v1.KeyValue attributes = 7;
 
-  // start_time_unix_nano is the last time when the aggregation value was reset
-  // to "zero". For some metric types this is ignored, see data types for more
-  // details.
+  // Labels is deprecated and will be removed soon.
+  // 1. Old senders and receivers that are not aware of this change will
+  // continue using the `labels` field.
+  // 2. New senders, which are aware of this change MUST send only `attributes`.
+  // 3. New receivers, which are aware of this change MUST convert this into
+  // `labels` by simply converting all int64 values into float.
   //
-  // The aggregation value is over the time interval (start_time_unix_nano,
-  // time_unix_nano].
+  // This field will be removed in ~3 months, on July 1, 2021.
+  repeated opentelemetry.proto.common.v1.StringKeyValue labels = 1 [deprecated = true];
+
+  // StartTimeUnixNano is optional but strongly encouraged, see the
+  // the detiled comments above Metric.
   //
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
-  //
-  // Value of 0 indicates that the timestamp is unspecified. In that case the
-  // timestamp may be decided by the backend.
   fixed64 start_time_unix_nano = 2;
 
-  // time_unix_nano is the moment when this aggregation value was reported.
+  // TimeUnixNano is required, see the detailed comments above Metric.
   //
   // Value is UNIX Epoch time in nanoseconds since 00:00:00 UTC on 1 January
   // 1970.
@@ -551,6 +607,12 @@ message DoubleSummaryDataPoint {
 
   // sum of the values in the population. If count is zero then this field
   // must be zero.
+  //
+  // Note: Sum should only be filled out when measuring non-negative discrete
+  // events, and is assumed to be monotonic over the values of these events.
+  // Negative events *can* be recorded, but sum should not be filled out when
+  // doing so.  This is specifically to enforce compatibility w/ OpenMetrics,
+  // see: https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#summary
   double sum = 5;
 
   // Represents the value at a given quantile of a distribution.
@@ -567,6 +629,8 @@ message DoubleSummaryDataPoint {
     double quantile = 1;
 
     // The value at the given quantile of a distribution.
+    //
+    // Quantile values must NOT be negative.
     double value = 2;
   }
 
@@ -580,6 +644,8 @@ message DoubleSummaryDataPoint {
 // was recorded, for example the span and trace ID of the active span when the
 // exemplar was recorded.
 message IntExemplar {
+  option deprecated = true;
+
   // The set of labels that were filtered out by the aggregator, but recorded
   // alongside the original measurement. Only labels that were filtered out
   // by the aggregator should be included
@@ -605,15 +671,26 @@ message IntExemplar {
   bytes trace_id = 5;
 }
 
-// A representation of an exemplar, which is a sample input double measurement.
+// A representation of an exemplar, which is a sample input measurement.
 // Exemplars also hold information about the environment when the measurement
 // was recorded, for example the span and trace ID of the active span when the
 // exemplar was recorded.
-message DoubleExemplar {
-  // The set of labels that were filtered out by the aggregator, but recorded
-  // alongside the original measurement. Only labels that were filtered out
-  // by the aggregator should be included
-  repeated opentelemetry.proto.common.v1.StringKeyValue filtered_labels = 1;
+message Exemplar {
+  // The set of key/value pairs that were filtered out by the aggregator, but
+  // recorded alongside the original measurement. Only key/value pairs that were
+  // filtered out by the aggregator should be included
+  repeated opentelemetry.proto.common.v1.KeyValue filtered_attributes = 7;
+
+  // Labels is deprecated and will be removed soon.
+  // 1. Old senders and receivers that are not aware of this change will
+  // continue using the `filtered_labels` field.
+  // 2. New senders, which are aware of this change MUST send only
+  // `filtered_attributes`.
+  // 3. New receivers, which are aware of this change MUST convert this into
+  // `filtered_labels` by simply converting all int64 values into float.
+  //
+  // This field will be removed in ~3 months, on July 1, 2021.
+  repeated opentelemetry.proto.common.v1.StringKeyValue filtered_labels = 1 [deprecated = true];
 
   // time_unix_nano is the exact time when this exemplar was recorded
   //
@@ -621,8 +698,13 @@ message DoubleExemplar {
   // 1970.
   fixed64 time_unix_nano = 2;
 
-  // Numerical double value of the measurement that was recorded.
-  double value = 3;
+  // Numerical value of the measurement that was recorded. An exemplar is
+  // considered invalid when one of the recognized value fields is not present
+  // inside this oneof.
+  oneof value {
+    double as_double = 3;
+    sfixed64 as_int = 6;
+  }
 
   // (Optional) Span ID of the exemplar trace.
   // span_id may be missing if the measurement is not recorded inside a trace
diff --git a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/trace/v1/trace.proto b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/trace/v1/trace.proto
index 004c2148c68..1513e52ee3e 100644
--- a/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/trace/v1/trace.proto
+++ b/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/opentelemetry/proto/trace/v1/trace.proto
@@ -32,6 +32,11 @@ message ResourceSpans {
 
   // A list of InstrumentationLibrarySpans that originate from a resource.
   repeated InstrumentationLibrarySpans instrumentation_library_spans = 2;
+
+  // This schema_url applies to the data in the "resource" field. It does not apply
+  // to the data in the "instrumentation_library_spans" field which have their own
+  // schema_url field.
+  string schema_url = 3;
 }
 
 // A collection of Spans produced by an InstrumentationLibrary.
@@ -43,6 +48,9 @@ message InstrumentationLibrarySpans {
 
   // A list of Spans that originate from an instrumentation library.
   repeated Span spans = 2;
+
+  // This schema_url applies to all spans and span events in the "spans" field.
+  string schema_url = 3;
 }
 
 // Span represents a single operation within a trace. Spans can be
@@ -107,7 +115,7 @@ message Span {
     SPAN_KIND_UNSPECIFIED = 0;
 
     // Indicates that the span represents an internal operation within an application,
-    // as opposed to an operations happening at the boundaries. Default value.
+    // as opposed to an operation happening at the boundaries. Default value.
     SPAN_KIND_INTERNAL = 1;
 
     // Indicates that the span covers server-side handling of an RPC or other
@@ -300,7 +308,7 @@ message Status {
   string message = 2;
 
   // For the semantics of status codes see
-  // https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/trace/api.md#set-status
+  // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#set-status
   enum StatusCode {
     // The default status.
     STATUS_CODE_UNSET               = 0;