diff --git a/CLIENT_SPECIFICATION.md b/CLIENT_SPECIFICATION.md
index 64d27879e..c431ac7b9 100644
--- a/CLIENT_SPECIFICATION.md
+++ b/CLIENT_SPECIFICATION.md
@@ -36,7 +36,7 @@ A number of arguments MUST be supported if a CLI is implemented:
 Argument		        | Meaning
 ------------------------|--------------------
 `--update`				| Updates the offline cache of pages.
-`--version`, `-v`		| Shows the current version of the client.
+`--version`, `-v`		| Shows the current version of the client, and the version of this specification that it implements.
 `--list-all`, `-a`		| Lists all the pages in the current platform to the standard output. One page name per line. Additional decoration MAY be printed to the standard error.
 
 Clients MAY support additional custom arguments not documented here.