diff --git a/teams.md/src/pages/templates/in-depth-guides/adaptive-cards/building-adaptive-cards.mdx b/teams.md/src/pages/templates/in-depth-guides/adaptive-cards/building-adaptive-cards.mdx
index 34df92dfc..87d25078c 100644
--- a/teams.md/src/pages/templates/in-depth-guides/adaptive-cards/building-adaptive-cards.mdx
+++ b/teams.md/src/pages/templates/in-depth-guides/adaptive-cards/building-adaptive-cards.mdx
@@ -32,6 +32,10 @@ Benefits:
 
 <LanguageInclude section="source-code-note" />
 
+:::note
+`AdaptiveCard` defaults the `version` property to `"1.5"`. The `version` field is required for Adaptive Cards to render on Teams mobile clients.
+:::
+
 ## Type‑safe Authoring & IntelliSense
 
 The package bundles the **Adaptive Card v1.5 schema** as strict <LanguageInclude section="language-name" /> types.