diff --git a/setup.py b/setup.py
index c807537..5e23820 100644
--- a/setup.py
+++ b/setup.py
@@ -54,9 +54,8 @@ def read(fname):
       },
       install_requires=[
           "mbed-ls>=1.5.1,==1.*",
-          "six",
-          "pyserial",
-          "pyOCD!=0.13.0"
+          "six==1.*",
+          "pyserial==3.*"
       ],
       classifiers=[
           "Development Status :: 5 - Production/Stable",