diff --git a/config/api/ams-api.yaml b/config/api/ams-api.yaml
index 34c99b6e10cbdd7012abecf291f8c266e725354e..aead8b5c6abea47429e5525a83edbec7f8d426b4 100644
--- a/config/api/ams-api.yaml
+++ b/config/api/ams-api.yaml
@@ -1,10 +1,10 @@
 openapi: 3.0.0
 info:
   title: 'ETSI GS MEC 021 Application Mobility Service API'
-  version: 2.2.1
+  version: 3.1.1
   description:
     'ETSI GS MEC 021 Application Mobility Service API described using OpenAPI.
-    <p>**Note**<br>MEC Sandbox supports a subset of AMS API endpoints; complete details on AMS API can be found on [ETSI Forge](https://www.etsi.org/deliver/etsi_gs/MEC/001_099/021/02.02.01_60/gs_mec021v020201p.pdf)'
+    <p>**Note**<br>MEC Sandbox supports a subset of AMS API endpoints; complete details on AMS API can be found on [ETSI Forge](https://www.etsi.org/deliver/etsi_gs/MEC/001_099/021/03.01.01_60/gs_mec021v030101p.pdf)'
   license:
     name: BSD-3-Clause
     url: 'https://forge.etsi.org/legal-matters'
@@ -13,8 +13,8 @@ info:
     email: cti_support@etsi.org
     url: https://forge.etsi.org/rep/mec/gs021-amsi-api
 externalDocs:
-  description: 'ETSI GS MEC 021 Application Mobility Service API, v2.2.1'
-  url: 'https://www.etsi.org/deliver/etsi_gs/MEC/001_099/021/02.02.01_60/gs_mec021v020201p.pdf'
+  description: 'ETSI GS MEC 021 Application Mobility Service API, v3.1.1'
+  url: 'https://www.etsi.org/deliver/etsi_gs/MEC/001_099/021/03.01.01_60/gs_mec021v030101p.pdf'
 servers:
   - url: 'https://localhost/sandboxname/amsi/v1'
 tags:
@@ -39,7 +39,7 @@ paths:
           explode: true
           schema:
             type: string
-        - name: all_fields
+        - name: All_fields
           in: query
           description: Include all complex attributes in the response.
           required: false
@@ -47,7 +47,7 @@ paths:
           explode: true
           schema:
             type: string
-        - name: fields
+        - name: Fields
           in: query
           description:
             Complex attributes to be included into the response. See clause
@@ -57,7 +57,7 @@ paths:
           explode: true
           schema:
             type: string
-        - name: exclude_fields
+        - name: Exclude_fields
           in: query
           description:
             Complex attributes to be excluded from the response.See clause
@@ -67,7 +67,7 @@ paths:
           explode: true
           schema:
             type: string
-        - name: exclude_default
+        - name: Exclude_default
           in: query
           description:
             Indicates to exclude the following complex attributes from the
@@ -147,46 +147,44 @@ paths:
         - name: filter
           in: query
           description:
-            Attribute-based filtering parameters according to ETSI GS MEC
-            011
+            Attribute-based filtering parameters, according to ETSI GS MEC 009, use the format (op,attr,value), 
+              e.g., (eq, appMobilityServiceId, value) or (gt, serviceConsumerId/appInstanceId, value)
           required: false
           style: form
           explode: true
           schema:
             type: string
-        - name: all_fields
+        - name: All_fields
           in: query
-          description: Include all complex attributes in the response.
+          description: Include all complex attributes in the response.e.g., All_Fields. 
           required: false
           style: form
           explode: true
           schema:
             type: string
-        - name: fields
+        - name: Fields
           in: query
           description:
-            Complex attributes to be included into the response. See clause
-            6.18 in ETSI GS MEC 011
+            Complex attributes to be included in the response (see Clause 6.18 in ETSI GS MEC 009), e.g., att or att/subatt.
           required: false
           style: form
           explode: true
           schema:
             type: string
-        - name: exclude_fields
+        - name: Exclude_fields
           in: query
           description:
-            Complex attributes to be excluded from the response.See clause
-            6.18 in ETSI GS MEC 011
+            Complex attributes to be excluded in the response (see Clause 6.18 in ETSI GS MEC 009), e.g., att or att/subatt.
           required: false
           style: form
           explode: true
           schema:
             type: string
-        - name: exclude_default
+        - name: Exclude_default
           in: query
           description:
             Indicates to exclude the following complex attributes from the
-            response  See clause 6.18 in ETSI GS MEC 011 for details.
+            response (See clause 6.18 in ETSI GS MEC 009 for details). 
           required: false
           style: form
           explode: true