diff --git a/setup.py b/setup.py
index 24101ace..e759d744 100644
--- a/setup.py
+++ b/setup.py
@@ -1,24 +1,9 @@
-import sys
 from setuptools import setup
 
 import versioneer
 
 commands = versioneer.get_cmdclass()
 
-DEV_REQUIREMENTS = [
-    "mock",
-    "tox",
-    "pyflakes",
-]
-if sys.version_info[0] < 3:
-    # txtorcon is not yet compatible with py3, so we include "txtorcon" in
-    # DEV_REQUIREMENTS under py2 but not under py3. The test suite will skip
-    # the tor tests when txtorcon is not importable. This results in
-    # different wheels when built under py2 vs py3 (with different
-    # extras_require[dev] dependencies), but I think this is ok, since nobody
-    # should be installing with [dev] from a wheel.
-    DEV_REQUIREMENTS.append("txtorcon")
-
 setup(name="magic-wormhole",
       version=versioneer.get_version(),
       description="Securely transfer data between computers",
@@ -53,8 +38,8 @@
       ],
       extras_require={
           ':sys_platform=="win32"': ["pypiwin32"],
-          "tor": ["txtorcon"],
-          "dev": DEV_REQUIREMENTS, # includes txtorcon on py2, but not py3
+          "tor": ["txtorcon >= 0.19.2"],
+          "dev": ["mock", "tox", "pyflakes", "txtorcon >= 0.19.2"],
       },
       test_suite="wormhole.test",
       cmdclass=commands,