diff --git a/rb/lib/selenium/webdriver/common/proxy.rb b/rb/lib/selenium/webdriver/common/proxy.rb
index 9ea94c0dfb294..644511575915e 100644
--- a/rb/lib/selenium/webdriver/common/proxy.rb
+++ b/rb/lib/selenium/webdriver/common/proxy.rb
@@ -77,6 +77,7 @@ def ==(other)
       alias eql? ==
 
       def ftp=(value)
+        WebDriver.logger.deprecate('FTP proxy support', nil, id: :ftp_proxy)
         self.type = :manual
         @ftp = value
       end