Clarify API behavior when older versions are called.

Signed-off-by: fonglh <fonglh@gmail.com>
(cherry picked from commit f62e24f697dd5c69e58f3b5d732fd5a962a0c8e6)
Signed-off-by: Tibor Vass <tibor@docker.com>

docs/reference/api/docker_remote_api.md

@@ -37,7 +37,8 @@ default.
 
 The current version of the API is v1.24 which means calling `/info` is the same
 as calling `/v1.24/info`. To call an older version of the API use
-`/v1.23/info`.
+`/v1.23/info`. If a newer daemon is installed, new properties may be returned
+even when calling older versions of the API.
 
 Use the table below to find the API version for a Docker version: