Notify player of old but unread messages.

mods/telex/init.lua

@@ -324,9 +324,16 @@ minetest.register_on_joinplayer(function(player)
 		telex.deliver(msgid)
 	end
 
-	if #nos > 0 then
-		--FIXME minetest.after()
-		minetest.chat_send_player(name, "You have " .. #nos .. " new message(s), use a terminal to read your messages");
+	-- notify if there wasn't anything new but the player still had some unread
+	if #old == 0 then
+		-- reuse `mbox`
+		for _, msgid in pairs(mbox) do
+			local msg = telex.get_msg(msgid)
+			if not msg.read then
+				minetest.chat_send_player(name, "You have unread messages")
+				break
+			end
+		end
 	end
 end)