diff --git a/README.md b/README.md
index 07865ba..605025e 100644
--- a/README.md
+++ b/README.md
@@ -918,11 +918,21 @@ bastille upgrade
 This sub-command lets you upgrade a release to a new release. Depending on the
 workflow this can be similar to a `bootstrap`.
 
+For standard containers you need to upgrade the shared base jail:
 ```shell
-ishmael ~ # bastille upgrade 11.3-RELEASE 12.0-RELEASE
+ishmael ~ # bastille upgrade 12.1-RELEASE 12.2-RELEASE
 ...
 ```
 
+For thick jails you need to upgrade every single container (according the freebsd-update procedure):
+```shell
+ishmael ~ # bastille upgrade folsom 12.2-RELEASE
+ishmael ~ # bastille upgrade folsom install
+...
+ishmael ~ # bastille restart folsom
+ishmael ~ # bastille upgrade folsom install
+```
+
 
 bastille verify
 ---------------