diff --git a/doc/source/admin/concurrency.rst b/doc/source/admin/concurrency.rst
index 52b12fa7cf..7a9fa1cf76 100644
--- a/doc/source/admin/concurrency.rst
+++ b/doc/source/admin/concurrency.rst
@@ -24,7 +24,7 @@ Selecting concurrency mode for a service
 Since nova 33.0.0 (2026.1 Gazpacho) the nova-scheduler, nova-api, and
 nova-metadata are using native threading by default. The rest of the
 services are using eventlet by default in this release. The concurrency mode
-can be configured via setting the environment variable
+can be configured per service via setting the environment variable
 ``OS_NOVA_DISABLE_EVENTLET_PATCHING``. Setting that variable to ``true``
 requests the native threading mode while setting it to ``false`` requests the
 eventlet mode. If the variable is not set the above default is applied.
@@ -37,6 +37,10 @@ eventlet mode. If the variable is not set the above default is applied.
    Since nova 33.0.0 (2026.1 Gazpacho) also the nova-conductor can be switched
    to native threading mode.
 
+   Since nova 33.0.0 (2026.1. Gazpacho) the nova-scheduler, nova-metadata, and
+   nova-api using native threading mode by default but still can be switched
+   back to eventlet if needed.
+
 
 Tunables for the native threading mode
 --------------------------------------
@@ -114,3 +118,14 @@ adding the `read_timeout`__ connection parameter to the connection string.
 
 We recommend using both in deployments where Nova services are running in
 native threading mode.
+
+Upgrading to nova 33.0.0 (2026.1. Gazpacho) or newer
+----------------------------------------------------
+
+In nova 33.0.0 (2026.1. Gazpacho) the default concurrency mode of
+nova-scheduler, nova-api, and nova-metadata service are switched to native
+threading. We recommend to decouple the upgrade from the concurrency mode
+change to reduce the risk of issues. To do that either test and tune the native
+threading mode of these services already in 2025.2 (Flamingo) or ensure that
+your service configuration is explicitly using the eventlet mode before you
+upgrade and only change to threading mode after the upgrade was successful.
diff --git a/releasenotes/notes/threading-by-default-sch-api-meta-d2534ce9c7b69d8a.yaml b/releasenotes/notes/threading-by-default-sch-api-meta-d2534ce9c7b69d8a.yaml
index f4dd831ed7..f874481c2c 100644
--- a/releasenotes/notes/threading-by-default-sch-api-meta-d2534ce9c7b69d8a.yaml
+++ b/releasenotes/notes/threading-by-default-sch-api-meta-d2534ce9c7b69d8a.yaml
@@ -3,7 +3,20 @@ features:
   - |
     The default concurrency mode is now switched from eventlet to native
     threading for nova-scheduler, nova-api, and nova-metadata services.
-    The concurrency mode can still be switched back to eventlet if needed.
-    Please read the
+    The concurrency mode can still be switched back to eventlet if needed
+    per service. Please read the
     `concurrency <https://docs.openstack.org/nova/latest/admin/concurrency.html>`__
     guide for more details.
+upgrade:
+  - |
+    When you are upgrading to 2026.1 (Gazpacho) or newer the default
+    configuration of nova-scheduler, nova-api, and nova-metadata services
+    change to run these services with native threading mode by default
+    instead of the legacy eventlet mode. We recommend to decouple the
+    upgrade from the concurrency mode change to reduce the risk of issues.
+    To do that either test the native threading mode of these services already
+    in 2025.2 (Flamingo) or ensure that your service configuration is
+    explicitly using the eventlet mode before you upgrade and only change to
+    threading mode after the upgrade was successful. Please read the
+    `concurrency <https://docs.openstack.org/nova/latest/admin/concurrency.html>`__
+    guide for more details on how to configure the mode.