diff --git a/setup.py b/setup.py
index f7c2fdb..5aa763d 100644
--- a/setup.py
+++ b/setup.py
@@ -53,7 +53,7 @@ setup(name="magic-wormhole",
           ':sys_platform=="win32"': ["pywin32"],
           "dev": ["mock", "tox", "pyflakes",
                   "magic-wormhole-transit-relay==0.1.1",
-                  "magic-wormhole-mailbox-server==0.2.0"],
+                  "magic-wormhole-mailbox-server==0.3.1"],
       },
       test_suite="wormhole.test",
       cmdclass=commands,