diff --git a/administrator/components/com_admin/sql/updates/mysql/5.1.1-2024-04-18.sql b/administrator/components/com_admin/sql/updates/mysql/5.1.1-2024-04-18.sql
new file mode 100644
index 0000000000000..8e59290ac5607
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/mysql/5.1.1-2024-04-18.sql
@@ -0,0 +1,10 @@
+--
+-- Add a default value for the colorScheme in the Atum template on Joomla update
+-- only when a value is not already set.
+-- New installs will have the default value set in the installation sql.
+--
+
+UPDATE `#__template_styles`
+SET `params` = JSON_SET(`params`, '$.colorScheme', 'os')
+WHERE `template` = 'atum'
+AND JSON_EXTRACT(`params`, '$.colorScheme') IS NULL;
diff --git a/administrator/components/com_admin/sql/updates/postgresql/5.1.1-2024-04-18.sql b/administrator/components/com_admin/sql/updates/postgresql/5.1.1-2024-04-18.sql
new file mode 100644
index 0000000000000..fc44f25a2a219
--- /dev/null
+++ b/administrator/components/com_admin/sql/updates/postgresql/5.1.1-2024-04-18.sql
@@ -0,0 +1,10 @@
+--
+-- Add a default value for the colorScheme in the Atum template on Joomla update
+-- only when a value is not already set.
+-- New installs will have the default value set in the installation sql.
+--
+
+UPDATE "#__template_styles"
+SET "params" = jsonb_set("params"::jsonb, '{colorScheme}', '"os"', true)
+WHERE "template" = 'atum'
+AND "params"::jsonb->>'colorScheme' IS NULL;