diff --git a/FlyingFox/Sources/HTTPStatusCode.swift b/FlyingFox/Sources/HTTPStatusCode.swift
index 1e8733e1..c843c66d 100644
--- a/FlyingFox/Sources/HTTPStatusCode.swift
+++ b/FlyingFox/Sources/HTTPStatusCode.swift
@@ -89,6 +89,9 @@ public extension HTTPStatusCode {
     static let expectationFailed                = HTTPStatusCode(417, phrase: "Expectation Failed")
     static let teapot                           = HTTPStatusCode(418, phrase: "I'm a teapot")
     static let misdirectedRequest               = HTTPStatusCode(421, phrase: "Misdirected Request")
+    static let unprocessableContent             = HTTPStatusCode(422, phrase: "Unprocessable Content")
+    static let locked                           = HTTPStatusCode(423, phrase: "Locked")
+    static let failedDependency                 = HTTPStatusCode(424, phrase: "Failed Dependency")
     static let tooEarly                         = HTTPStatusCode(425, phrase: "Too Early")
     static let upgradeRequired                  = HTTPStatusCode(426, phrase: "Upgrade Required")
     static let preconditionRequired             = HTTPStatusCode(428, phrase: "Precondition Required")
diff --git a/FlyingFox/Tests/HTTPStatusCodeTests.swift b/FlyingFox/Tests/HTTPStatusCodeTests.swift
index 3e2be8ba..097a6732 100644
--- a/FlyingFox/Tests/HTTPStatusCodeTests.swift
+++ b/FlyingFox/Tests/HTTPStatusCodeTests.swift
@@ -83,6 +83,9 @@ final class HTTPStatusCodeTests: XCTestCase {
         XCTAssertEqual(HTTPStatusCode.expectationFailed, HTTPStatusCode(417, phrase: "Expectation Failed"))
         XCTAssertEqual(HTTPStatusCode.teapot, HTTPStatusCode(418, phrase: "I'm a teapot"))
         XCTAssertEqual(HTTPStatusCode.misdirectedRequest, HTTPStatusCode(421, phrase: "Misdirected Request"))
+        XCTAssertEqual(HTTPStatusCode.unprocessableContent, HTTPStatusCode(422, phrase: "Unprocessable Content"))
+        XCTAssertEqual(HTTPStatusCode.locked, HTTPStatusCode(423, phrase: "Locked"))
+        XCTAssertEqual(HTTPStatusCode.failedDependency, HTTPStatusCode(424, phrase: "Failed Dependency"))
         XCTAssertEqual(HTTPStatusCode.tooEarly, HTTPStatusCode(425, phrase: "Too Early"))
         XCTAssertEqual(HTTPStatusCode.upgradeRequired, HTTPStatusCode(426, phrase: "Upgrade Required"))
         XCTAssertEqual(HTTPStatusCode.preconditionRequired, HTTPStatusCode(428, phrase: "Precondition Required"))