diff --git a/doc/source/microversion_testing.rst b/doc/source/microversion_testing.rst
index c22888d..325b19f 100644
--- a/doc/source/microversion_testing.rst
+++ b/doc/source/microversion_testing.rst
@@ -354,6 +354,10 @@
 
   .. _2.48: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id43
 
+  * `2.55`_
+
+  .. _2.55: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id49
+
   * `2.60`_
 
   .. _2.60: https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id54
diff --git a/releasenotes/notes/add-update-flavor--api-to-flavors-client-a859542fe54aab7c.yaml b/releasenotes/notes/add-update-flavor--api-to-flavors-client-a859542fe54aab7c.yaml
new file mode 100644
index 0000000..222a99f
--- /dev/null
+++ b/releasenotes/notes/add-update-flavor--api-to-flavors-client-a859542fe54aab7c.yaml
@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    Add update flavor API to compute flavors_client library.
diff --git a/tempest/api/compute/admin/test_flavors_microversions.py b/tempest/api/compute/admin/test_flavors_microversions.py
new file mode 100644
index 0000000..027af25
--- /dev/null
+++ b/tempest/api/compute/admin/test_flavors_microversions.py
@@ -0,0 +1,43 @@
+# Copyright 2018 NEC Corporation.
+# All Rights Reserved.
+#
+#    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.
+from tempest.api.compute import base
+from tempest.lib.common.utils import data_utils
+from tempest.lib import decorators
+
+
+class FlavorsV255TestJSON(base.BaseV2ComputeAdminTest):
+    min_microversion = '2.55'
+    max_microversion = 'latest'
+
+    # NOTE(gmann): This class tests the flavors APIs
+    # response schema for the 2.55 microversion.
+
+    @decorators.idempotent_id('61976b25-488d-41dc-9dcb-cb9693a7b075')
+    def test_crud_flavor(self):
+        flavor_id = data_utils.rand_int_id(start=1000)
+        # Checking create API response schema
+        new_flavor_id = self.create_flavor(ram=512,
+                                           vcpus=1,
+                                           disk=10,
+                                           id=flavor_id)['id']
+        # Checking show API response schema
+        self.flavors_client.show_flavor(new_flavor_id)['flavor']
+        # Checking update API response schema
+        self.admin_flavors_client.update_flavor(new_flavor_id,
+                                                description='new')['flavor']
+        # Checking list details API response schema
+        self.flavors_client.list_flavors(detail=True)['flavors']
+        # Checking list API response schema
+        self.flavors_client.list_flavors()['flavors']
diff --git a/tempest/lib/api_schema/response/compute/v2_1/flavors.py b/tempest/lib/api_schema/response/compute/v2_1/flavors.py
index 547d94d..af5e67f 100644
--- a/tempest/lib/api_schema/response/compute/v2_1/flavors.py
+++ b/tempest/lib/api_schema/response/compute/v2_1/flavors.py
@@ -86,7 +86,7 @@
     'status_code': [200]
 }
 
-create_get_flavor_details = {
+create_update_get_flavor_details = {
     'status_code': [200],
     'response_body': {
         'type': 'object',
diff --git a/tempest/lib/api_schema/response/compute/v2_55/__init__.py b/tempest/lib/api_schema/response/compute/v2_55/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tempest/lib/api_schema/response/compute/v2_55/__init__.py
diff --git a/tempest/lib/api_schema/response/compute/v2_55/flavors.py b/tempest/lib/api_schema/response/compute/v2_55/flavors.py
new file mode 100644
index 0000000..823190a
--- /dev/null
+++ b/tempest/lib/api_schema/response/compute/v2_55/flavors.py
@@ -0,0 +1,112 @@
+# Copyright 2018 NEC Corporation.  All rights reserved.
+#
+#    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.
+
+from tempest.lib.api_schema.response.compute.v2_1 import parameter_types
+
+# Note(gmann): This is schema for microversion 2.55 which includes the
+# following changes:
+# Add new PUT API
+# Adds a ``description`` field to the following APIs response:
+#    - ``GET /flavors``
+#    - ``GET /flavors/detail``
+#    - ``GET /flavors/{flavor_id}``
+#    - ``POST /flavors``
+
+flavor_description = {
+    'type': ['string', 'null'],
+    'minLength': 0, 'maxLength': 65535
+}
+
+list_flavors = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'flavors': {
+                'type': 'array',
+                'items': {
+                    'type': 'object',
+                    'properties': {
+                        'name': {'type': 'string'},
+                        'links': parameter_types.links,
+                        'id': {'type': 'string'},
+                        'description': flavor_description
+                    },
+                    'additionalProperties': False,
+                    'required': ['name', 'links', 'id', 'description']
+                }
+            },
+            'flavors_links': parameter_types.links
+        },
+        'additionalProperties': False,
+        # NOTE(gmann): flavors_links attribute is not necessary
+        # to be present always So it is not 'required'.
+        'required': ['flavors']
+    }
+}
+
+common_flavor_info = {
+    'type': 'object',
+    'properties': {
+        'name': {'type': 'string'},
+        'links': parameter_types.links,
+        'ram': {'type': 'integer'},
+        'vcpus': {'type': 'integer'},
+        # 'swap' attributes comes as integer value but if it is empty
+        # it comes as "". So defining type of as string and integer.
+        'swap': {'type': ['integer', 'string']},
+        'disk': {'type': 'integer'},
+        'id': {'type': 'string'},
+        'OS-FLV-DISABLED:disabled': {'type': 'boolean'},
+        'os-flavor-access:is_public': {'type': 'boolean'},
+        'rxtx_factor': {'type': 'number'},
+        'OS-FLV-EXT-DATA:ephemeral': {'type': 'integer'},
+        'description': flavor_description
+    },
+    'additionalProperties': False,
+    # 'OS-FLV-DISABLED', 'os-flavor-access', 'rxtx_factor' and
+    # 'OS-FLV-EXT-DATA' are API extensions. So they are not 'required'.
+    'required': ['name', 'links', 'ram', 'vcpus', 'swap', 'disk', 'id',
+                 'description']
+}
+
+list_flavors_details = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'flavors': {
+                'type': 'array',
+                'items': common_flavor_info
+            },
+            # NOTE(gmann): flavors_links attribute is not necessary
+            # to be present always So it is not 'required'.
+            'flavors_links': parameter_types.links
+        },
+        'additionalProperties': False,
+        'required': ['flavors']
+    }
+}
+
+create_update_get_flavor_details = {
+    'status_code': [200],
+    'response_body': {
+        'type': 'object',
+        'properties': {
+            'flavor': common_flavor_info
+        },
+        'additionalProperties': False,
+        'required': ['flavor']
+    }
+}
diff --git a/tempest/lib/services/compute/flavors_client.py b/tempest/lib/services/compute/flavors_client.py
index 0fb1991..4923d7e 100644
--- a/tempest/lib/services/compute/flavors_client.py
+++ b/tempest/lib/services/compute/flavors_client.py
@@ -21,12 +21,18 @@
     as schema_access
 from tempest.lib.api_schema.response.compute.v2_1 import flavors_extra_specs \
     as schema_extra_specs
+from tempest.lib.api_schema.response.compute.v2_55 import flavors \
+    as schemav255
 from tempest.lib.common import rest_client
 from tempest.lib.services.compute import base_compute_client
 
 
 class FlavorsClient(base_compute_client.BaseComputeClient):
 
+    schema_versions_info = [
+        {'min': None, 'max': '2.54', 'schema': schema},
+        {'min': '2.55', 'max': None, 'schema': schemav255}]
+
     def list_flavors(self, detail=False, **params):
         """Lists flavors.
 
@@ -36,11 +42,12 @@
         https://developer.openstack.org/api-ref/compute/#list-flavors-with-details
         """
         url = 'flavors'
-        _schema = schema.list_flavors
-
+        schema = self.get_schema(self.schema_versions_info)
         if detail:
             url += '/detail'
             _schema = schema.list_flavors_details
+        else:
+            _schema = schema.list_flavors
         if params:
             url += '?%s' % urllib.urlencode(params)
 
@@ -58,7 +65,9 @@
         """
         resp, body = self.get("flavors/%s" % flavor_id)
         body = json.loads(body)
-        self.validate_response(schema.create_get_flavor_details, resp, body)
+        schema = self.get_schema(self.schema_versions_info)
+        self.validate_response(schema.create_update_get_flavor_details,
+                               resp, body)
         return rest_client.ResponseBody(resp, body)
 
     def create_flavor(self, **kwargs):
@@ -77,7 +86,25 @@
         resp, body = self.post('flavors', post_body)
 
         body = json.loads(body)
-        self.validate_response(schema.create_get_flavor_details, resp, body)
+        schema = self.get_schema(self.schema_versions_info)
+        self.validate_response(schema.create_update_get_flavor_details,
+                               resp, body)
+        return rest_client.ResponseBody(resp, body)
+
+    def update_flavor(self, flavor_id, **kwargs):
+        """Uodate the flavor or instance type.
+
+        For a full list of available parameters, please refer to the official
+        API reference:
+        https://developer.openstack.org/api-ref/compute/#update-flavor-description
+        """
+        put_body = json.dumps({'flavor': kwargs})
+        resp, body = self.put("flavors/%s" % flavor_id, put_body)
+
+        body = json.loads(body)
+        schema = self.get_schema(self.schema_versions_info)
+        self.validate_response(schema.create_update_get_flavor_details,
+                               resp, body)
         return rest_client.ResponseBody(resp, body)
 
     def delete_flavor(self, flavor_id):
diff --git a/tempest/tests/lib/services/compute/test_flavors_client.py b/tempest/tests/lib/services/compute/test_flavors_client.py
index cbd17c6..5325036 100644
--- a/tempest/tests/lib/services/compute/test_flavors_client.py
+++ b/tempest/tests/lib/services/compute/test_flavors_client.py
@@ -17,6 +17,7 @@
 import fixtures
 from oslo_serialization import jsonutils as json
 
+from tempest.api.compute import api_microversion_fixture
 from tempest.lib.services.compute import flavors_client
 from tempest.tests.lib import fake_auth_provider
 from tempest.tests.lib import fake_http
@@ -39,6 +40,21 @@
         "vcpus": 1
     }
 
+    FAKE_FLAVOR_UPDATE = {
+        "disk": 1,
+        "id": "1",
+        "links": [{
+            "href": "http://openstack.example.com/v2/openstack/flavors/1",
+            "rel": "self"}, {
+            "href": "http://openstack.example.com/openstack/flavors/1",
+            "rel": "bookmark"}],
+        "name": "m1.tiny",
+        "ram": 512,
+        "swap": 1,
+        "vcpus": 1,
+        "description": 'new'
+    }
+
     EXTRA_SPECS = {"extra_specs": {
         "key1": "value1",
         "key2": "value2"}
@@ -106,6 +122,25 @@
     def test_create_flavor__byte_body(self):
         self._test_create_flavor(bytes_body=True)
 
+    def _test_update_flavor(self, bytes_body=False):
+        self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+            '2.55'))
+        expected = {"flavor": TestFlavorsClient.FAKE_FLAVOR_UPDATE}
+        request = {"flavor": {"description": "updated description"}}
+        self.check_service_client_function(
+            self.client.update_flavor,
+            'tempest.lib.common.rest_client.RestClient.put',
+            expected,
+            bytes_body,
+            flavor_id='8c7aae5a-d315-4216-875b-ed9b6a5bcfc6',
+            **request)
+
+    def test_update_flavor_str_body(self):
+        self._test_update_flavor(bytes_body=False)
+
+    def test_update_flavor__byte_body(self):
+        self._test_update_flavor(bytes_body=True)
+
     def test_delete_flavor(self):
         self.check_service_client_function(
             self.client.delete_flavor,