diff -r 7dd7cdb43181 -r 7395f6e68dba plugins/mod_csi_simple.lua
--- a/plugins/mod_csi_simple.lua	Sun May 10 23:06:21 2020 +0200
+++ b/plugins/mod_csi_simple.lua	Sun May 10 23:09:15 2020 +0200
@@ -16,8 +16,9 @@
 local important_payloads = module:get_option_set("csi_important_payloads", { });
 
 function is_important(stanza) --> boolean, reason: string
-	if type(stanza) == "string" then
-		-- whitespace pings etc
+	if stanza == " " then
+		return true, "whitespace keepalive";
+	elseif type(stanza) == "string" then
 		return true, "raw data";
 	elseif not st.is_stanza(stanza) then
 		return true;