diff --git a/rfcs/text/0009-data_stream-fields.md b/rfcs/text/0009-data_stream-fields.md
index d138f94bdf..7018d1fe51 100644
--- a/rfcs/text/0009-data_stream-fields.md
+++ b/rfcs/text/0009-data_stream-fields.md
@@ -1,7 +1,7 @@
 # 0009: Data stream fields
 <!-- Leave this ID at 0000. The ECS team will assign a unique, contiguous RFC number upon merging the initial stage of this RFC. -->
 
-- Stage: **2 (draft)** <!-- Update to reflect target stage. See https://elastic.github.io/ecs/stages.html -->
+- Stage: **3 (finished)** <!-- Update to reflect target stage. See https://elastic.github.io/ecs/stages.html -->
 - Date: **2021-01-04** <!-- The ECS team sets this date at merge time. This is the date of the latest stage advancement. -->
 
 When introducing the new indexing strategy for Elastic Agent which uses data streams, we found that adding a few [constant_keyword](https://www.elastic.co/guide/en/elasticsearch/reference/master/keyword.html#constant-keyword-field-type) fields corresponding to the central components in the new indexing strategy would be advantageous.
@@ -35,7 +35,7 @@ The fields can be found in `rfcs/text/0009/data_stream.yml`.
 
 ### Restrictions on values
 
-Due to the fact that the values of the `data_stream` fields make up the data stream name, the restrictions on data stream names also apply to values for the `data_stream` fields. As an example, they cannot include \, /, *, ?, ", <, >, |, ` `. Please see the Elasticsearch reference for [restrictions on index/data stream names](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-create-index.html#indices-create-api-path-params). Here follows the _additional_ restrictions imposed on the data stream fields:
+Due to the fact that the values of the `data_stream` fields make up the data stream name, the restrictions on data stream names also apply to values for the `data_stream` fields. As an example, they cannot include `\`, `/`, `*`, `?`, `"`, `<`, `>`, `|`, ` `, `,`, `#`. Please see the Elasticsearch reference for [restrictions on index/data stream names](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-create-index.html#indices-create-api-path-params). Here follows the _additional_ restrictions imposed on the data stream fields:
 
 **data_stream.type**
 
@@ -246,7 +246,7 @@ e.g.:
 * Previous discussion on [dataset fields](https://github.com/elastic/ecs/pull/845)
 * Discussion on [field value restrictions](https://github.com/elastic/kibana/issues/75846)
 * Restrictions on [index names](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-create-index.html)
-
+* Blog post: [An introduction to the Elastic data stream naming scheme](https://www.elastic.co/blog/an-introduction-to-the-elastic-data-stream-naming-scheme)
 
 ### RFC Pull Requests
 
diff --git a/rfcs/text/0009/data_stream.yml b/rfcs/text/0009/data_stream.yml
index df974cf096..bd236b1ebb 100644
--- a/rfcs/text/0009/data_stream.yml
+++ b/rfcs/text/0009/data_stream.yml
@@ -5,7 +5,7 @@
   description: >
     The data_stream fields are part defining the new data stream naming scheme.
 
-    In the new data stream naming scheme the value of the data stream fields combine to the name of the actual data stream in the following manner `{data_stream.type}-{data_stream.dataset}-{data_stream.namespace}`. This means the fields can only contain characters that are valid as part of names of data streams. More details about this can be found in this blog post. TODO: Add link to blog post
+    In the new data stream naming scheme the value of the data stream fields combine to the name of the actual data stream in the following manner `{data_stream.type}-{data_stream.dataset}-{data_stream.namespace}`. This means the fields can only contain characters that are valid as part of names of data streams. More details about this can be found in this [blog post](https://www.elastic.co/blog/an-introduction-to-the-elastic-data-stream-naming-scheme).
 
     Due to the fact that the values of the `data_stream` fields make up the data stream name, the restrictions on data stream names also apply to values for the `data_stream` fields. As an example, they cannot include \, /, *, ?, ", <, >, |, ` `. Please see the Elasticsearch reference for [restrictions on index/data stream names](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-create-index.html#indices-create-api-path-params).