migration-guide: Kirkstone is now 4.0

Update the docs to reflect that kirkstone is 4.0, not 3.5.

(From yocto-docs rev: a6f571ad5b087385cad8765ed455c4b4eaeebca6)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 3 insertions, 3 deletions

diff --git a/documentation/migration-guides/index.rst b/documentation/migration-guides/index.rst
index d45ba31e7e..20c6ab9d4e 100644
--- a/documentation/migration-guides/index.rst
+++ b/documentation/migration-guides/index.rst
@@ -12,7 +12,7 @@ to move to one release of the Yocto Project from the previous one.
 .. toctree::
 
    migration-general
-   migration-3.5
+   migration-4.0
    migration-3.4
    migration-3.3
    migration-3.2
diff --git a/documentation/migration-guides/migration-3.5.rst b/documentation/migration-guides/migration-4.0.rst
index 8a4c568743..202999ece8 100644
--- a/documentation/migration-guides/migration-3.5.rst
+++ b/documentation/migration-guides/migration-4.0.rst
@@ -1,8 +1,8 @@
-Release 3.5 (kirkstone)
+Release 4.0 (kirkstone)
 =======================
 
 This section provides migration information for moving to the Yocto
-Project 3.5 Release (codename "kirkstone") from the prior release.
+Project 4.0 Release (codename "kirkstone") from the prior release.
 
 Recipe changes
 --------------