diff --git a/.zuul.yaml b/.zuul.yaml
index 1cf67b0..c794d26 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -143,25 +143,24 @@
     voting: false
 
 - job:
-    name: tempest-scenario-all
+    name: tempest-slow
     parent: tempest-multinode-full
     branches:
       - master
     description: |
-      This multinode integration job will run all scenario tests including slow
-      tests with lvm multibackend setup. This job will not run any API tests.
+      This multinode integration job will run all the tests tagged as slow.
+      It enables the lvm multibackend setup to cover few scenario tests.
+      This job will run only slow tests(API or Scenario) serially.
 
       Former names for this job were:
         * legacy-tempest-dsvm-neutron-scenario-multinode-lvm-multibackend
         * tempest-scenario-multinode-lvm-multibackend
     timeout: 10800
     vars:
-      # 'all' is used for applying the custom regex below.
-      tox_envlist: all
+      tox_envlist: slow-serial
       devstack_localrc:
         CINDER_ENABLED_BACKENDS: lvm:lvmdriver-1,lvm:lvmdriver-2
       tempest_concurrency: 2
-      tempest_test_regex: (^tempest\.(scenario))
 
 - job:
     name: tempest-full-queens
@@ -353,7 +352,7 @@
               - ^tempest/hacking/.*$
               - ^tempest/tests/.*$
         - tempest-tox-plugin-sanity-check
-        - tempest-scenario-all:
+        - tempest-slow:
             irrelevant-files:
               - ^(test-|)requirements.txt$
               - ^.*\.rst$
@@ -363,7 +362,6 @@
               - ^setup.cfg$
               - ^tempest/hacking/.*$
               - ^tempest/tests/.*$
-              - ^tempest/api/.*$
         - nova-cells-v1:
             irrelevant-files:
               - ^(test-|)requirements.txt$
@@ -397,7 +395,7 @@
               - ^setup.cfg$
               - ^tempest/hacking/.*$
               - ^tempest/tests/.*$
-        - tempest-scenario-all:
+        - tempest-slow:
             irrelevant-files:
               - ^(test-|)requirements.txt$
               - ^.*\.rst$
@@ -407,7 +405,6 @@
               - ^setup.cfg$
               - ^tempest/hacking/.*$
               - ^tempest/tests/.*$
-              - ^tempest/api/.*$
     experimental:
       jobs:
         - tempest-cinder-v2-api:
diff --git a/tempest/api/identity/admin/v3/test_list_projects.py b/tempest/api/identity/admin/v3/test_list_projects.py
index 82664e8..148b368 100644
--- a/tempest/api/identity/admin/v3/test_list_projects.py
+++ b/tempest/api/identity/admin/v3/test_list_projects.py
@@ -18,7 +18,19 @@
 from tempest.lib import decorators
 
 
-class ListProjectsTestJSON(base.BaseIdentityV3AdminTest):
+class BaseListProjectsTestJSON(base.BaseIdentityV3AdminTest):
+
+    def _list_projects_with_params(self, included, excluded, params, key):
+        # Validate that projects in ``included`` belongs to the projects
+        # returned that match ``params`` but not projects in ``excluded``
+        body = self.projects_client.list_projects(params)['projects']
+        for p in included:
+            self.assertIn(p[key], map(lambda x: x[key], body))
+        for p in excluded:
+            self.assertNotIn(p[key], map(lambda x: x[key], body))
+
+
+class ListProjectsTestJSON(BaseListProjectsTestJSON):
 
     @classmethod
     def resource_setup(cls):
@@ -61,17 +73,20 @@
     def test_list_projects_with_domains(self):
         # List projects with domain
         self._list_projects_with_params(
-            {'domain_id': self.domain['id']}, 'domain_id')
+            [self.p1], [self.p2, self.p3], {'domain_id': self.domain['id']},
+            'domain_id')
 
     @decorators.idempotent_id('0fe7a334-675a-4509-b00e-1c4b95d5dae8')
     def test_list_projects_with_enabled(self):
         # List the projects with enabled
-        self._list_projects_with_params({'enabled': False}, 'enabled')
+        self._list_projects_with_params(
+            [self.p1], [self.p2, self.p3], {'enabled': False}, 'enabled')
 
     @decorators.idempotent_id('fa178524-4e6d-4925-907c-7ab9f42c7e26')
     def test_list_projects_with_name(self):
         # List projects with name
-        self._list_projects_with_params({'name': self.p1_name}, 'name')
+        self._list_projects_with_params(
+            [self.p1], [self.p2, self.p3], {'name': self.p1_name}, 'name')
 
     @decorators.idempotent_id('6edc66f5-2941-4a17-9526-4073311c1fac')
     def test_list_projects_with_parent(self):
@@ -82,8 +97,3 @@
         self.assertNotEmpty(fetched_projects)
         for project in fetched_projects:
             self.assertEqual(self.p3['parent_id'], project['parent_id'])
-
-    def _list_projects_with_params(self, params, key):
-        body = self.projects_client.list_projects(params)['projects']
-        self.assertIn(self.p1[key], map(lambda x: x[key], body))
-        self.assertNotIn(self.p2[key], map(lambda x: x[key], body))
diff --git a/tempest/api/network/admin/test_external_network_extension.py b/tempest/api/network/admin/test_external_network_extension.py
index 39d03e7..7e8cc8e 100644
--- a/tempest/api/network/admin/test_external_network_extension.py
+++ b/tempest/api/network/admin/test_external_network_extension.py
@@ -13,6 +13,7 @@
 import testtools
 
 from tempest.api.network import base
+from tempest.common import utils
 from tempest import config
 from tempest.lib.common.utils import data_utils
 from tempest.lib.common.utils import test_utils
@@ -95,7 +96,6 @@
         self.assertEqual(self.network['id'], show_net['id'])
         self.assertFalse(show_net['router:external'])
 
-    @decorators.skip_because(bug="1749820")
     @decorators.idempotent_id('82068503-2cf2-4ed4-b3be-ecb89432e4bb')
     @testtools.skipUnless(CONF.network_feature_enabled.floating_ips,
                           'Floating ips are not availabled')
@@ -118,8 +118,15 @@
         self.addCleanup(test_utils.call_and_ignore_notfound_exc,
                         self.admin_floating_ips_client.delete_floatingip,
                         created_floating_ip['id'])
-        floatingip_list = self.admin_floating_ips_client.list_floatingips(
-            network=external_network['id'])
+        if utils.is_extension_enabled('filter-validation', 'network'):
+            floatingip_list = self.admin_floating_ips_client.list_floatingips(
+                floating_network_id=external_network['id'])
+        else:
+            # NOTE(hongbin): This is for testing the backward-compatibility
+            # of neutron API although the parameter is a wrong filter
+            # for listing floating IPs.
+            floatingip_list = self.admin_floating_ips_client.list_floatingips(
+                invalid_filter=external_network['id'])
         self.assertIn(created_floating_ip['id'],
                       (f['id'] for f in floatingip_list['floatingips']))
         self.admin_networks_client.delete_network(external_network['id'])
diff --git a/tempest/lib/api_schema/response/compute/v2_3/servers.py b/tempest/lib/api_schema/response/compute/v2_3/servers.py
index f24103e..969df3b 100644
--- a/tempest/lib/api_schema/response/compute/v2_3/servers.py
+++ b/tempest/lib/api_schema/response/compute/v2_3/servers.py
@@ -163,4 +163,13 @@
     }
 }
 
+# NOTE: Below are the unchanged schema in this microversion. We need
+# to keep this schema in this file to have the generic way to select the
+# right schema based on self.schema_versions_info mapping in service client.
+# ****** Schemas unchanged since microversion 2.1 ***
 list_servers = copy.deepcopy(servers.list_servers)
+update_server = copy.deepcopy(servers.update_server)
+rebuild_server = copy.deepcopy(servers.rebuild_server)
+rebuild_server_with_admin_pass = copy.deepcopy(
+    servers.rebuild_server_with_admin_pass)
+show_server_diagnostics = copy.deepcopy(servers.show_server_diagnostics)
diff --git a/tempest/lib/api_schema/response/compute/v2_6/servers.py b/tempest/lib/api_schema/response/compute/v2_6/servers.py
index 934098f..d5774de 100644
--- a/tempest/lib/api_schema/response/compute/v2_6/servers.py
+++ b/tempest/lib/api_schema/response/compute/v2_6/servers.py
@@ -16,9 +16,18 @@
 
 from tempest.lib.api_schema.response.compute.v2_3 import servers
 
+# NOTE: Below are the unchanged schema in this microversion. We need
+# to keep this schema in this file to have the generic way to select the
+# right schema based on self.schema_versions_info mapping in service client.
+# ****** Schemas unchanged since microversion 2.3 ******
 list_servers = copy.deepcopy(servers.list_servers)
 get_server = copy.deepcopy(servers.get_server)
 list_servers_detail = copy.deepcopy(servers.list_servers_detail)
+update_server = copy.deepcopy(servers.update_server)
+rebuild_server = copy.deepcopy(servers.rebuild_server)
+rebuild_server_with_admin_pass = copy.deepcopy(
+    servers.rebuild_server_with_admin_pass)
+show_server_diagnostics = copy.deepcopy(servers.show_server_diagnostics)
 
 # NOTE: The consolidated remote console API got introduced with v2.6
 # with bp/consolidate-console-api. See Nova commit 578bafeda
diff --git a/tox.ini b/tox.ini
index de4f1b7..befa991 100644
--- a/tox.ini
+++ b/tox.ini
@@ -135,6 +135,16 @@
     find . -type f -name "*.pyc" -delete
     tempest run --serial --regex '\[.*\bsmoke\b.*\]' {posargs}
 
+[testenv:slow-serial]
+envdir = .tox/tempest
+sitepackages = {[tempestenv]sitepackages}
+setenv = {[tempestenv]setenv}
+deps = {[tempestenv]deps}
+# The regex below is used to select the slow tagged tests to run serially:
+commands =
+    find . -type f -name "*.pyc" -delete
+    tempest run --serial --regex '\[.*\bslow\b.*\]' {posargs}
+
 [testenv:venv]
 deps =
   -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}