Add ChangeLog and migration guide entries
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/ChangeLog.d/cipher-delayed-output.txt b/ChangeLog.d/cipher-delayed-output.txt
new file mode 100644
index 0000000..0c8f7db
--- /dev/null
+++ b/ChangeLog.d/cipher-delayed-output.txt
@@ -0,0 +1,6 @@
+API changes
+ * For multi-part AEAD operations with the Cipher module, calling
+ mbedtls_cipher_finish() is now mandatory. Previously the documentation
+ was unclear on this point, and this function happened to never do
+ anything with the currently implemented AEADs, so in practice is was
+ possible to skip calling it, which is no longer supported.