diff --git a/lib/google/apis/core/api_command.rb b/lib/google/apis/core/api_command.rb
index 1df7d6240bf..9262f87dc00 100644
--- a/lib/google/apis/core/api_command.rb
+++ b/lib/google/apis/core/api_command.rb
@@ -52,6 +52,9 @@ class ApiCommand < HttpCommand
         #
         # @return [void]
         def prepare!
+          if options && options.api_format_version
+            header['X-Goog-Api-Format-Version'] = options.api_format_version.to_s
+          end
           query[FIELDS_PARAM] = normalize_fields_param(query[FIELDS_PARAM]) if query.key?(FIELDS_PARAM)
           if request_representation && request_object
             header['Content-Type'] ||= JSON_CONTENT_TYPE
@@ -100,15 +103,15 @@ def decode_response_body(content_type, body)
         def check_status(status, header = nil, body = nil, message = nil)
           case status
           when 400, 402...500
-            error = parse_error(body)
-            if error
-              message = sprintf('%s: %s', error['reason'], error['message'])
-              raise ERROR_REASON_MAPPING[error['reason']].new(
+            reason, message = parse_error(body)
+            if reason
+              message = sprintf('%s: %s', reason, message)
+              raise ERROR_REASON_MAPPING[reason].new(
                 message,
                 status_code: status,
                 header: header,
                 body: body
-              ) if ERROR_REASON_MAPPING.key?(error['reason'])
+              ) if ERROR_REASON_MAPPING.key?(reason)
             end
             super(status, header, body, message)
           else
@@ -122,15 +125,45 @@ def allow_form_encoding?
 
         private
 
-        # Attempt to parse a JSON error message, returning the first found error
+        # Attempt to parse a JSON error message
         # @param [String] body
         #  HTTP response body
-        # @return [Hash]
+        # @return [Array<(String, String)>]
+        #   Error reason and message
         def parse_error(body)
-          hash = JSON.load(body)
-          hash['error']['errors'].first
+          obj = JSON.load(body)
+          error = obj['error']
+          if error['details']
+            return extract_v2_error_details(error)
+          elsif error['errors']
+            return extract_v1_error_details(error)
+          else
+            fail 'Can not parse error message. No "details" or "errors" detected'
+          end
         rescue
-          nil
+          return [nil, nil]
+        end
+
+        # Extracts details from a v1 error message
+        # @param [Hash] error
+        #  Parsed JSON
+        # @return [Array<(String, String)>]
+        #   Error reason and message
+        def extract_v1_error_details(error)
+          reason = error['errors'].first['reason']
+          message = error['message']
+          return [reason, message]
+        end
+
+        # Extracts details from a v2error message
+        # @param [Hash] error
+        #  Parsed JSON
+        # @return [Array<(String, String)>]
+        #   Error reason and message
+        def extract_v2_error_details(error)
+          reason = error['status']
+          message = error['message']
+          return [reason, message]
         end
 
         # Convert field names from ruby conventions to original names in JSON
diff --git a/lib/google/apis/core/json_representation.rb b/lib/google/apis/core/json_representation.rb
index bfc1e49d91e..9b7e5444185 100644
--- a/lib/google/apis/core/json_representation.rb
+++ b/lib/google/apis/core/json_representation.rb
@@ -139,7 +139,7 @@ def from_json(json)
           end
         end
 
-        def to_json
+        def to_json(*a)
           representation = self.class.const_get(:Representation)
           representation.new(self).to_json(user_options: { skip_undefined: true })
         end
diff --git a/lib/google/apis/options.rb b/lib/google/apis/options.rb
index 83f6def9eda..69be662a687 100644
--- a/lib/google/apis/options.rb
+++ b/lib/google/apis/options.rb
@@ -30,7 +30,8 @@ module Apis
       :header,
       :normalize_unicode,
       :skip_serialization,
-      :skip_deserialization)
+      :skip_deserialization,
+      :api_format_version)
 
     # General client options
     class ClientOptions
@@ -67,6 +68,8 @@ class RequestOptions
       #   @return [Boolean] True if body object should be treated as raw text instead of an object.
       # @!attribute [rw] skip_deserialization
       #   @return [Boolean] True if response should be returned in raw form instead of deserialized.
+      # @!attribute [rw] api_format_version
+      #   @return [Fixnum] Version of the error format to request/expect.
 
       # Get the default options
       # @return [Google::Apis::RequestOptions]
@@ -85,7 +88,7 @@ def merge(options)
         new_options
       end
     end
-    
+
     ClientOptions.default.log_http_requests = false
     ClientOptions.default.application_name = 'unknown'
     ClientOptions.default.application_version = '0.0.0'
@@ -93,5 +96,6 @@ def merge(options)
     RequestOptions.default.normalize_unicode = false
     RequestOptions.default.skip_serialization = false
     RequestOptions.default.skip_deserialization = false
+    RequestOptions.default.api_format_version = nil
   end
 end
diff --git a/spec/google/apis/core/api_command_spec.rb b/spec/google/apis/core/api_command_spec.rb
index c14634169c4..6b57863bb15 100644
--- a/spec/google/apis/core/api_command_spec.rb
+++ b/spec/google/apis/core/api_command_spec.rb
@@ -280,4 +280,52 @@
       expect { command.execute(client) }.to raise_error(/Invalid request/)
     end
   end
+
+  context('with v2 error messages') do
+    let(:command) do
+      cmd = Google::Apis::Core::ApiCommand.new(:get, 'https://www.googleapis.com/zoo/animals')
+      cmd.options.api_format_version = 2
+      cmd
+    end
+
+    before(:example) do
+      json = <<EOF
+{
+  "error": {
+    "code": 400,
+    "message": "Illegal character ':' in log name",
+    "status": "INVALID_ARGUMENT",
+    "details": [
+      {
+        "@type": "type.googleapis.com/google.logging.v2.WriteLogEntriesPartialErrors",
+        "logEntryErrors": {
+          "0": {
+            "code": 3,
+            "message": "Illegal character ':' in log name"
+          },
+          "1": {
+            "code": 7,
+            "message": "User not authorized."
+          }
+        }
+      }
+    ]
+  }
+}
+EOF
+
+      stub_request(:get, 'https://www.googleapis.com/zoo/animals')
+        .with(headers: {'X-Goog-Api-Format-Version' => '2'})
+        .to_return(status: [400, 'Invalid Argument'], headers: { 'Content-Type' => 'application/json' }, body: json)
+    end
+
+    it 'should raise client error' do
+      expect { command.execute(client) }.to raise_error(Google::Apis::ClientError)
+    end
+
+    it 'should raise an error with the reason and message' do
+      expect { command.execute(client) }.to raise_error(
+        /INVALID_ARGUMENT: Illegal character ':' in log name/)
+    end
+  end
 end