diff --git a/README.md b/README.md
index aeaa2c7..fc1a367 100644
--- a/README.md
+++ b/README.md
@@ -371,6 +371,14 @@ This is a destructive command; do not run it on an existing database!
 
 See [the separate build documentation](doc/build.md).
 
+## Running a custom GitLab version
+
+It is not recommended to make changes to any of the files in `/opt/gitlab`
+after installing omnibus-gitlab: they will either conflict with or be
+overwritten by future updates. If you want to run a custom version of GitLab
+you can [build your own package](doc/build.md) or use [another installation
+method][CE README].
+
 ## Acknowledgments
 
 This omnibus installer project is based on the awesome work done by Chef in
--
libgit2 0.21.2