Deprecated lower case epic sort enum values

Use upper case enum values instead
of lower case

doc/api/graphql/reference/index.md

@@ -7485,10 +7485,14 @@ Roadmap sort values.
 
 | Value | Description |
 | ----- | ----------- |
-| `end_date_asc` | End date at ascending order. |
-| `end_date_desc` | End date at descending order. |
-| `start_date_asc` | Start date at ascending order. |
-| `start_date_desc` | Start date at descending order. |
+| `END_DATE_ASC` | Sort by end date in ascending order. |
+| `END_DATE_DESC` | Sort by end date in descending order. |
+| `START_DATE_ASC` | Sort by start date in ascending order. |
+| `START_DATE_DESC` | Sort by start date in descending order. |
+| `end_date_asc` **{warning-solid}** | **Deprecated:** Use END_DATE_ASC. Deprecated in 13.11. |
+| `end_date_desc` **{warning-solid}** | **Deprecated:** Use END_DATE_DESC. Deprecated in 13.11. |
+| `start_date_asc` **{warning-solid}** | **Deprecated:** Use START_DATE_ASC. Deprecated in 13.11. |
+| `start_date_desc` **{warning-solid}** | **Deprecated:** Use START_DATE_DESC. Deprecated in 13.11. |
 
 ### `EpicState`
 

ee/app/graphql/types/epic_sort_enum.rb

@@ -5,9 +5,16 @@ module Types
     graphql_name 'EpicSort'
     description 'Roadmap sort values'
 
-    value 'start_date_desc', 'Start date at descending order.', value: :start_date_desc
-    value 'start_date_asc', 'Start date at ascending order.', value: :start_date_asc
-    value 'end_date_desc', 'End date at descending order.', value: :end_date_desc
-    value 'end_date_asc', 'End date at ascending order.', value: :end_date_asc
+    # Deprecated, as we prefer uppercase enums
+    # https://gitlab.com/groups/gitlab-org/-/epics/1838
+    value 'start_date_desc', 'Start date at descending order.', value: :start_date_desc, deprecated: { reason: 'Use START_DATE_DESC', milestone: '13.11' }
+    value 'start_date_asc', 'Start date at ascending order.', value: :start_date_asc, deprecated: { reason: 'Use START_DATE_ASC', milestone: '13.11' }
+    value 'end_date_desc', 'End date at descending order.', value: :end_date_desc, deprecated: { reason: 'Use END_DATE_DESC', milestone: '13.11' }
+    value 'end_date_asc', 'End date at ascending order.', value: :end_date_asc, deprecated: { reason: 'Use END_DATE_ASC', milestone: '13.11' }
+
+    value 'START_DATE_DESC', 'Sort by start date in descending order.', value: :start_date_desc
+    value 'START_DATE_ASC', 'Sort by start date in ascending order.', value: :start_date_asc
+    value 'END_DATE_DESC', 'Sort by end date in descending order.', value: :end_date_desc
+    value 'END_DATE_ASC', 'Sort by end date in ascending order.', value: :end_date_asc
   end
 end