diff --git a/cps-rest/src/main/resources/static/components.yml b/cps-rest/src/main/resources/static/components.yml
index 51a49a6..75a6f99 100644
--- a/cps-rest/src/main/resources/static/components.yml
+++ b/cps-rest/src/main/resources/static/components.yml
@@ -158,6 +158,14 @@
       schema:
         type: boolean
         default: false
+    observedTimestampInQuery:
+      name: observed-timestamp
+      in: query
+      description: observed-timestamp
+      required: false
+      schema:
+        type: string
+        example: '2021-03-21T00:10:34.030-0100'
 
   responses:
     NotFound:
diff --git a/cps-rest/src/main/resources/static/cpsData.yml b/cps-rest/src/main/resources/static/cpsData.yml
index 9c4f333..75d9544 100644
--- a/cps-rest/src/main/resources/static/cpsData.yml
+++ b/cps-rest/src/main/resources/static/cpsData.yml
@@ -55,6 +55,7 @@
       - $ref: 'components.yml#/components/parameters/dataspaceNameInPath'
       - $ref: 'components.yml#/components/parameters/anchorNameInPath'
       - $ref: 'components.yml#/components/parameters/requiredXpathInQuery'
+      - $ref: 'components.yml#/components/parameters/observedTimestampInQuery'
     requestBody:
       required: true
       content:
@@ -81,6 +82,7 @@
       - $ref: 'components.yml#/components/parameters/dataspaceNameInPath'
       - $ref: 'components.yml#/components/parameters/anchorNameInPath'
       - $ref: 'components.yml#/components/parameters/requiredXpathInQuery'
+      - $ref: 'components.yml#/components/parameters/observedTimestampInQuery'
     requestBody:
       required: true
       content:
@@ -107,6 +109,7 @@
       - $ref: 'components.yml#/components/parameters/dataspaceNameInPath'
       - $ref: 'components.yml#/components/parameters/anchorNameInPath'
       - $ref: 'components.yml#/components/parameters/requiredXpathInQuery'
+      - $ref: 'components.yml#/components/parameters/observedTimestampInQuery'
     responses:
       '204':
         $ref: 'components.yml#/components/responses/NoContent'
@@ -128,6 +131,7 @@
       - $ref: 'components.yml#/components/parameters/dataspaceNameInPath'
       - $ref: 'components.yml#/components/parameters/anchorNameInPath'
       - $ref: 'components.yml#/components/parameters/xpathInQuery'
+      - $ref: 'components.yml#/components/parameters/observedTimestampInQuery'
     requestBody:
       required: true
       content:
@@ -154,6 +158,7 @@
       - $ref: 'components.yml#/components/parameters/dataspaceNameInPath'
       - $ref: 'components.yml#/components/parameters/anchorNameInPath'
       - $ref: 'components.yml#/components/parameters/xpathInQuery'
+      - $ref: 'components.yml#/components/parameters/observedTimestampInQuery'
     requestBody:
       required: true
       content:
@@ -180,6 +185,7 @@
       - $ref: 'components.yml#/components/parameters/dataspaceNameInPath'
       - $ref: 'components.yml#/components/parameters/anchorNameInPath'
       - $ref: 'components.yml#/components/parameters/xpathInQuery'
+      - $ref: 'components.yml#/components/parameters/observedTimestampInQuery'
     requestBody:
       required: true
       content: