diff --git a/docs/abra/upgrade.md b/docs/abra/upgrade.md
index 0deace0..de24b38 100644
--- a/docs/abra/upgrade.md
+++ b/docs/abra/upgrade.md
@@ -57,6 +57,15 @@ And test things work.
 
 > 🎺🎺🎺 Get the [release candidate](https://git.coopcloud.tech/toolshed/abra/releases/tag/0.10.0-rc1-beta) 🎺🎺🎺
 
+* `abra` will now write the app deployment version to the app env file
+  (`$ABRA_DIR/servers/<server>/<domain>.env`) against the `TYPE=/RECIPE=` env
+  var. This has a number of implications which are detailed in the [release
+  announcement
+  post](https://pad.local-it.org/G1TOcidEQtyArJU9gI0SDw?both#New-abra-release-candidate).
+  The current `v0.9.x` series of `abra` will not be able to parse this version.
+  So, if you're testing the release candidate, you might to clean up your
+  `.env` files afterwards.
+
 * We have finally migrated from [`urfave/cli`](https://github.com/urfave/cli)
   to [`spf13/cobra`](https://cobra.dev) as our command-line handling library.
   This means we should (hopefully!) not have to deal with so many command-line