diff --git a/code/API_definitions/connected-network-type-subscriptions.yaml b/code/API_definitions/connected-network-type-subscriptions.yaml
index d300f008..128acc18 100644
--- a/code/API_definitions/connected-network-type-subscriptions.yaml
+++ b/code/API_definitions/connected-network-type-subscriptions.yaml
@@ -458,7 +458,9 @@ components:
             - PLAIN
             - ACCESSTOKEN
             - REFRESHTOKEN
-          description: "The type of the credential."
+          description: |
+            The type of the credential.
+            Note: Type of the credential - MUST be set to ACCESSTOKEN for now
       discriminator:
         propertyName: credentialType
         mapping:
@@ -498,7 +500,13 @@ components:
             accessTokenExpiresUtc:
               type: string
               format: date-time
-              description: REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired. In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+              description: |
+                REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired.
+                In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+                If the access token is a JWT and registered "exp" (Expiration Time) claim is present, the two expiry times should match.
+                It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+                Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+              example: "2023-07-03T12:27:08.312Z"
             accessTokenType:
               description: REQUIRED. Type of the access token (See [OAuth 2.0](https://tools.ietf.org/html/rfc6749#section-7.1)).
               type: string
@@ -522,7 +530,13 @@ components:
             accessTokenExpiresUtc:
               type: string
               format: date-time
-              description: REQUIRED. An absolute UTC instant at which the token shall be considered expired.
+              description: |
+                REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired.
+                In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+                If the access token is a JWT and registered "exp" (Expiration Time) claim is present, the two expiry times should match.
+                It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+                Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+              example: "2023-07-03T12:27:08.312Z"
             accessTokenType:
               description: REQUIRED. Type of the access token (See [OAuth 2.0](https://tools.ietf.org/html/rfc6749#section-7.1)).
               type: string
@@ -615,11 +629,19 @@ components:
         startsAt:
           type: string
           format: date-time
-          description: Date when the event subscription will begin/began
+          description: |
+            Date when the event subscription will begin/began
+            It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+            Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+          example: "2023-07-03T12:27:08.312Z"
         expiresAt:
           type: string
           format: date-time
-          description: Date when the event subscription will expire. Only provided when `subscriptionExpireTime` is indicated by API client or Telco Operator has specific policy about that.
+          description: |
+            Date when the event subscription will expire. Only provided when `subscriptionExpireTime` is indicated by API client or Telco Operator has specific policy about that.
+            It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+            Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+          example: "2023-07-03T12:27:08.312Z"
         status:
           type: string
           description: |-
diff --git a/code/API_definitions/device-reachability-status-subscriptions.yaml b/code/API_definitions/device-reachability-status-subscriptions.yaml
index d1812d52..746fb4e3 100644
--- a/code/API_definitions/device-reachability-status-subscriptions.yaml
+++ b/code/API_definitions/device-reachability-status-subscriptions.yaml
@@ -477,7 +477,9 @@ components:
             - PLAIN
             - ACCESSTOKEN
             - REFRESHTOKEN
-          description: "The type of the credential."
+          description: |
+            The type of the credential.
+            Note: Type of the credential - MUST be set to ACCESSTOKEN for now
       discriminator:
         propertyName: credentialType
         mapping:
@@ -517,7 +519,13 @@ components:
             accessTokenExpiresUtc:
               type: string
               format: date-time
-              description: REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired. In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+              description: |
+                REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired.
+                In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+                If the access token is a JWT and registered "exp" (Expiration Time) claim is present, the two expiry times should match.
+                It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+                Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+              example: "2023-07-03T12:27:08.312Z"
             accessTokenType:
               description: REQUIRED. Type of the access token (See [OAuth 2.0](https://tools.ietf.org/html/rfc6749#section-7.1)).
               type: string
@@ -541,7 +549,13 @@ components:
             accessTokenExpiresUtc:
               type: string
               format: date-time
-              description: REQUIRED. An absolute UTC instant at which the token shall be considered expired.
+              description: |
+                REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired.
+                In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+                If the access token is a JWT and registered "exp" (Expiration Time) claim is present, the two expiry times should match.
+                It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+                Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+              example: "2023-07-03T12:27:08.312Z"
             accessTokenType:
               description: REQUIRED. Type of the access token (See [OAuth 2.0](https://tools.ietf.org/html/rfc6749#section-7.1)).
               type: string
@@ -631,11 +645,19 @@ components:
         startsAt:
           type: string
           format: date-time
-          description: Date when the event subscription will begin/began
+          description: |
+            Date when the event subscription will begin/began
+            It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+            Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+          example: "2023-07-03T12:27:08.312Z"
         expiresAt:
           type: string
           format: date-time
-          description: Date when the event subscription will expire. Only provided when `subscriptionExpireTime` is indicated by API client or Telco Operator has specific policy about that.
+          description: |
+            Date when the event subscription will expire. Only provided when `subscriptionExpireTime` is indicated by API client or Telco Operator has specific policy about that.
+            It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+            Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+          example: "2023-07-03T12:27:08.312Z"
         status:
           type: string
           description: |-
diff --git a/code/API_definitions/device-roaming-status-subscriptions.yaml b/code/API_definitions/device-roaming-status-subscriptions.yaml
index 0ed6e436..aa5e7a20 100644
--- a/code/API_definitions/device-roaming-status-subscriptions.yaml
+++ b/code/API_definitions/device-roaming-status-subscriptions.yaml
@@ -498,7 +498,9 @@ components:
             - PLAIN
             - ACCESSTOKEN
             - REFRESHTOKEN
-          description: "The type of the credential."
+          description: |
+            The type of the credential.
+            Note: Type of the credential - MUST be set to ACCESSTOKEN for now
       discriminator:
         propertyName: credentialType
         mapping:
@@ -538,7 +540,13 @@ components:
             accessTokenExpiresUtc:
               type: string
               format: date-time
-              description: REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired. In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+              description: |
+                REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired.
+                In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+                If the access token is a JWT and registered "exp" (Expiration Time) claim is present, the two expiry times should match.
+                It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+                Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+              example: "2023-07-03T12:27:08.312Z"
             accessTokenType:
               description: REQUIRED. Type of the access token (See [OAuth 2.0](https://tools.ietf.org/html/rfc6749#section-7.1)).
               type: string
@@ -562,7 +570,13 @@ components:
             accessTokenExpiresUtc:
               type: string
               format: date-time
-              description: REQUIRED. An absolute UTC instant at which the token shall be considered expired.
+              description: |
+                REQUIRED. An absolute (UTC) timestamp at which the token shall be considered expired.
+                In the case of an ACCESS_TOKEN_EXPIRED termination reason, implementation should notify the client before the expiration date.
+                If the access token is a JWT and registered "exp" (Expiration Time) claim is present, the two expiry times should match.
+                It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+                Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+              example: "2023-07-03T12:27:08.312Z"
             accessTokenType:
               description: REQUIRED. Type of the access token (See [OAuth 2.0](https://tools.ietf.org/html/rfc6749#section-7.1)).
               type: string
@@ -659,11 +673,19 @@ components:
         startsAt:
           type: string
           format: date-time
-          description: Date when the event subscription will begin/began
+          description: |
+            Date when the event subscription will begin/began
+            It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+            Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+          example: "2023-07-03T12:27:08.312Z"
         expiresAt:
           type: string
           format: date-time
-          description: Date when the event subscription will expire. Only provided when `subscriptionExpireTime` is indicated by API client or Telco Operator has specific policy about that.
+          description: |
+            Date when the event subscription will expire. Only provided when `subscriptionExpireTime` is indicated by API client or Telco Operator has specific policy about that.
+            It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.
+            Recommended format is yyyy-MM-dd'T'HH:mm:ss.SSSZ (i.e. which allows 2023-07-03T14:27:08.312+02:00 or 2023-07-03T12:27:08.312Z)
+          example: "2023-07-03T12:27:08.312Z"
         status:
           type: string
           description: |-