diff --git a/README.md b/README.md
index 20d6316..0162708 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,7 @@
 - [git-crypt](https://www.agwa.name/projects/git-crypt/)
 - [Python](https://python.org/) 3
 - [Poetry](https://python-poetry.org/)
+- target servers: best tested with Debian GNU/Linux 11 (bullseye)
 
 ### Install packages