--- a/testing/geckodriver/CHANGES.md
+++ b/testing/geckodriver/CHANGES.md
@@ -1,13 +1,21 @@
 Change log
 ==========
 
 All notable changes to this program is documented in this file.
 
+Unreleased
+----------
+
+### Removed
+
+- Removed `socksUsername` and `socksPassword` because both are no longer
+  valid keys for proxy capabilities
+
 
 0.19.0 (2017-09-16)
 -------------------
 
 Note that with geckodriver v0.19.0 the following versions are recommended:
 - Firefox 55.0 (and greater)
 - Selenium 3.5 (and greater)
 

--- a/testing/geckodriver/README.md
+++ b/testing/geckodriver/README.md
@@ -180,34 +180,16 @@ geckodriver supports a number of [capabi
  </tr>
 
  <tr>
   <td><code>socksVersion</code>
   <td>number
   <td>Defines the SOCKS proxy version. This property has only to be set
    when <code>proxyType</code> is set to <code>manual</code>.
  </tr>
-
- <tr>
-  <td><code>socksUsername</code>
-  <td>string
-  <td>Defines the username used
-   when authenticating with a SOCKS proxy.
-   This property should only be set
-   when <code>proxyType</code> is <code>manual</code>.
- </tr>
-
- <tr>
-  <td><code>socksPassword</code>
-  <td>string
-  <td>Defines the password used
-   when authenticating with a SOCKS proxy.
-   This property should only be set
-   when <code>proxyType</code> is <code>manual</code>.
- </tr>
 </table>
 
 
 Firefox capabilities
 ====================
 
 geckodriver also supports a capability named `moz:firefoxOptions`
 which takes Firefox-specific options.

--- a/testing/webdriver/src/capabilities.rs
+++ b/testing/webdriver/src/capabilities.rs
@@ -174,24 +174,16 @@ impl SpecNewSessionParameters {
                 "httpProxy" => try!(SpecNewSessionParameters::validate_host(value)),
                 "noProxy" => try!(SpecNewSessionParameters::validate_no_proxy(value)),
                 "sslProxy" => try!(SpecNewSessionParameters::validate_host(value)),
                 "socksProxy" => try!(SpecNewSessionParameters::validate_host(value)),
                 "socksVersion" => if !value.is_number() {
                     return Err(WebDriverError::new(ErrorStatus::InvalidArgument,
                                                    "socksVersion was not a number"))
                 },
-                "socksUsername" => if !value.is_string() {
-                    return Err(WebDriverError::new(ErrorStatus::InvalidArgument,
-                                                   "socksUsername was not a string"))
-                },
-                "socksPassword" => if !value.is_string() {
-                    return Err(WebDriverError::new(ErrorStatus::InvalidArgument,
-                                                   "socksPassword was not a string"))
-                },
                 x => return Err(WebDriverError::new(
                     ErrorStatus::InvalidArgument,
                     format!("{} was not a valid proxy configuration capability", x)))
             }
         }
         Ok(())
     }