diff --git a/content/copilot/concepts/knowledge-bases.md b/content/copilot/concepts/knowledge-bases.md
index 65e12a3ab3..9ce8a377e4 100644
--- a/content/copilot/concepts/knowledge-bases.md
+++ b/content/copilot/concepts/knowledge-bases.md
@@ -13,9 +13,13 @@ redirect_from:
 contentType: concepts
 ---
 
-> [!TIP] If you're looking for a more flexible way to organize context for {% data variables.product.prodname_copilot_short %}, you can also try {% data variables.copilot.copilot_spaces %}.
->
-> {% data variables.copilot.copilot_spaces_short %} let you combine code and free-text content—like transcripts or specs—and can be created by any {% data variables.product.prodname_copilot_short %} user, not just organization owners. They’re a good option for more focused or task-specific use cases. See [AUTOTITLE](/copilot/using-github-copilot/copilot-spaces/about-organizing-and-sharing-context-with-copilot-spaces).
+<!-- expires 2025-09-11 -->
+
+<!-- When this expires, check with the stakeholder for release #6165 if the knowledge bases content can be deleted -->
+
+>[!IMPORTANT] Beginning September 12, 2025, knowledge bases will be {% data variables.release-phases.retired %} and fully replaced by {% data variables.copilot.copilot_spaces %}. {% data variables.copilot.copilot_spaces_short %} let you combine code and free-text content—like transcripts or specs—and can be created by any {% data variables.product.prodname_copilot_short %} user, not just organization owners. They’re a good option for more focused or task-specific use cases. See [AUTOTITLE](/copilot/using-github-copilot/copilot-spaces/about-organizing-and-sharing-context-with-copilot-spaces).
+
+<!-- end expires 2025-09-11 -->
 
 ## About knowledge bases
 
@@ -26,4 +30,4 @@ When you ask a question in {% data variables.copilot.copilot_chat_short %} with
 ## Next steps
 
 * To learn how to create and manage knowledge bases, see [AUTOTITLE](/copilot/how-tos/context/creating-and-managing-copilot-knowledge-bases).
-* To learn how to use knowledge bases in {% data variables.copilot.copilot_chat_short %}, see [AUTOTITLE](/copilot/how-tos/chat/asking-github-copilot-questions-in-github#asking-copilot-chat-questions-about-a-knowledge-base) and [AUTOTITLE](/copilot/how-tos/chat/asking-github-copilot-questions-in-your-ide#asking-a-question-about-a-knowledge-base).
+* To learn how to use knowledge bases, see [AUTOTITLE](/copilot/how-tos/provide-context/use-knowledge-bases).
diff --git a/content/copilot/how-tos/provide-context/create-knowledge-bases.md b/content/copilot/how-tos/provide-context/create-knowledge-bases.md
index 7c5641756e..c96aa3a6da 100644
--- a/content/copilot/how-tos/provide-context/create-knowledge-bases.md
+++ b/content/copilot/how-tos/provide-context/create-knowledge-bases.md
@@ -25,6 +25,13 @@ redirect_from:
   - /copilot/how-tos/context/create-knowledge-bases
 contentType: how-tos
 ---
+<!-- expires 2025-09-11 -->
+
+<!-- When this expires, check with the stakeholder for release #6165 if the knowledge bases content can be deleted -->
+
+>[!IMPORTANT] Beginning September 12, 2025, knowledge bases will be {% data variables.release-phases.retired %} and fully replaced by {% data variables.copilot.copilot_spaces %}. {% data variables.copilot.copilot_spaces_short %} let you combine code and free-text content—like transcripts or specs—and can be created by any {% data variables.product.prodname_copilot_short %} user, not just organization owners. They’re a good option for more focused or task-specific use cases. See [AUTOTITLE](/copilot/using-github-copilot/copilot-spaces/about-organizing-and-sharing-context-with-copilot-spaces).
+
+<!-- end expires 2025-09-11 -->
 
 Knowledge bases are a way to bring together Markdown documentation across one or more repositories. When you ask a question in {% data variables.copilot.copilot_chat_short %} with a knowledge base selected, {% data variables.product.prodname_copilot_short %} will search the knowledge base for relevant information and synthesize a response.
 
diff --git a/content/copilot/how-tos/provide-context/use-knowledge-bases.md b/content/copilot/how-tos/provide-context/use-knowledge-bases.md
index cf383216d4..d681dc4b51 100644
--- a/content/copilot/how-tos/provide-context/use-knowledge-bases.md
+++ b/content/copilot/how-tos/provide-context/use-knowledge-bases.md
@@ -12,6 +12,14 @@ redirect_from:
 contentType: how-tos
 ---
 
+<!-- expires 2025-09-11 -->
+
+<!-- When this expires, check with the stakeholder for release #6165 if the knowledge bases content can be deleted -->
+
+>[!IMPORTANT] Beginning September 12, 2025, knowledge bases will be {% data variables.release-phases.retired %} and fully replaced by {% data variables.copilot.copilot_spaces %}. {% data variables.copilot.copilot_spaces_short %} let you combine code and free-text content—like transcripts or specs—and can be created by any {% data variables.product.prodname_copilot_short %} user, not just organization owners. They’re a good option for more focused or task-specific use cases. See [AUTOTITLE](/copilot/using-github-copilot/copilot-spaces/about-organizing-and-sharing-context-with-copilot-spaces).
+
+<!-- end expires 2025-09-11 -->
+
 ## Introduction
 
 Knowledge bases are collections of documentation that you can use to provide context for your questions in {% data variables.copilot.copilot_chat %}. Knowledge bases are useful when you want to ask questions about a specific topic or set of topics, and you want the answers to be informed by the relevant documentation.