diff --git a/doc/source/reference/process.rst b/doc/source/reference/process.rst
index 45378eb8b2..be5dce8988 100644
--- a/doc/source/reference/process.rst
+++ b/doc/source/reference/process.rst
@@ -206,6 +206,15 @@ Week before milestone-1
 Milestone-1
 ===========
 
+#. Ensure that all trailing projects have been branched for the previous
+   series.
+
+   - List unbranched projects using::
+
+       tools/list_unbranched_projects.sh
+
+   - Propose a patch to branch the missing ones.
+
 #. Propose autoreleases for cycle-with-intermediary libraries which
    did not release since the previous release.
 
diff --git a/doc/source/reference/using.rst b/doc/source/reference/using.rst
index d7c095d1e4..72e57a45c7 100644
--- a/doc/source/reference/using.rst
+++ b/doc/source/reference/using.rst
@@ -833,6 +833,24 @@ deliverable become EOL, this tool aim to list projects that have been declared
 EOL on a series that is EM and where the corresponding series branch
 still exists.
 
+tools/list_unbranched_projects.sh
+---------------------------------
+
+A script to detect deliverables who haven't been branched during previous
+series.
+
+Example:
+
+::
+
+  tools/list_unbranched_projects.sh
+
+This tooling aim to avoid to miss branching. This is a side effect of
+the trailing projects, each series some of them are missed and remain
+unbranched. We faced similar use case previously and that leaded us to
+issues during releasing on stable branches.
+
+
 tools/membership_freeze_test.py
 --------------------------------
 
diff --git a/openstack_releases/cmds/list_em_series.py b/openstack_releases/cmds/list_series.py
similarity index 79%
rename from openstack_releases/cmds/list_em_series.py
rename to openstack_releases/cmds/list_series.py
index c0f59e9905..ed7a374f47 100644
--- a/openstack_releases/cmds/list_em_series.py
+++ b/openstack_releases/cmds/list_series.py
@@ -19,8 +19,16 @@ BASE_PATH = os.path.dirname(os.path.realpath(__file__))
 ROOT_DIR = f'{BASE_PATH}/../../data'
 
 
-def main():
+def em():
     series = series_status.SeriesStatus.from_directory(ROOT_DIR)
     for serie in series:
         if series.get(serie).is_em:
             print(serie)
+
+
+def maintained():
+    series = series_status.SeriesStatus.from_directory(ROOT_DIR)
+    for serie in series:
+        if series.get(serie).is_maintained:
+            if serie != 'independent':
+                print(serie)
diff --git a/openstack_releases/series_status.py b/openstack_releases/series_status.py
index 051df75c9b..523734c250 100644
--- a/openstack_releases/series_status.py
+++ b/openstack_releases/series_status.py
@@ -51,6 +51,10 @@ class Series(object):
     def is_em(self):
         return self.status == 'extended maintenance'
 
+    @property
+    def is_maintained(self):
+        return self.status == 'maintained' or self.status == 'development'
+
 
 class SeriesStatus(collections.abc.Mapping):
 
diff --git a/setup.cfg b/setup.cfg
index 2702e088ec..dfe76edc3c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -24,7 +24,8 @@ packages = openstack_releases
 console_scripts =
     validate-request = openstack_releases.cmds.validate:main
     list-changes = openstack_releases.cmds.list_changes:main
-    list-em-series = openstack_releases.cmds.list_em_series:main
+    list-em-series = openstack_releases.cmds.list_series:em
+    list-maintained-series = openstack_releases.cmds.list_series:maintained
     list-unreleased-changes = openstack_releases.cmds.list_unreleased_changes:main
     list-constraints = openstack_releases.cmds.list_constraints:main
     new-release = openstack_releases.cmds.new_release:main
diff --git a/tools/list_unbranched_projects.sh b/tools/list_unbranched_projects.sh
new file mode 100755
index 0000000000..60025b743c
--- /dev/null
+++ b/tools/list_unbranched_projects.sh
@@ -0,0 +1,63 @@
+#!/bin/bash
+#
+#    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.
+function help {
+# Display helping message
+cat <<EOF
+usage: $0 [<args>]
+
+Retrieve unbranched projects for maintained series.
+Can be used to retrieve branch inconsistencies on maintained series.
+
+Arguments:
+    -d, --debug         Turn on the debug mode
+    -h, --help          show this help message and exit
+examples:
+    $(basename $0)
+EOF
+}
+
+for i in "$@"; do
+    case $i in
+        # Turn on the debug mode
+        -d|--debug)
+        set -x
+        shift 1
+        ;;
+        # Display the helping message
+        -h|--help)
+        help
+        exit 0
+        ;;
+    esac
+done
+
+
+GERRIT_URL="https://review.opendev.org"
+TOOLSDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+BASEDIR=$(dirname $TOOLSDIR)
+source $TOOLSDIR/functions
+enable_tox_venv
+
+series=($(list-maintained-series))
+
+# Make sure no pager is configured so the output is not blocked
+export PAGER=
+
+for current_series in "${series[@]}"; do
+    echo -e "\nUnbranched projects for ${current_series}:\n"
+    grep -L "stable/${current_series}" ${BASEDIR}/deliverables/${current_series}/*.yaml | \
+        sed 's@'"${BASEDIR}"'\/@@g' | \
+        grep -v tempest | \
+        grep -v patrol
+done