diff --git a/src/docs/markdown/service.md b/src/docs/markdown/service.md
index 35c6e77..d6edd97 100644
--- a/src/docs/markdown/service.md
+++ b/src/docs/markdown/service.md
@@ -108,7 +108,7 @@ For example, if you need to define environment variables for use in your config,
 Environment="CF_API_TOKEN=super-secret-cloudflare-tokenvalue"
 ```
 
-Or, for example if you need to change the config file from the default of the Caddyfile, to instead using a JSON file:
+Or, for example if you need to change the config file from the default of the Caddyfile, to instead using a JSON file (note that `Exec*` directives [must be reset with empty strings](https://www.freedesktop.org/software/systemd/man/systemd.service.html#ExecStart=) before setting a new value):
 ```systemd
 [Service]
 ExecStart=