diff --git a/requirements.txt b/requirements.txt
index 55e3acd3e..c21ac0e01 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-cython>=0.24,<0.27.0
+cython>=0.24,<0.28.0
 pathlib
 numpy>=1.7
 cymem>=1.30,<1.32
@@ -15,5 +15,5 @@ ftfy>=4.4.2,<5.0.0
 pytest>=3.0.6,<4.0.0
 mock>=2.0.0,<3.0.0
 msgpack-python
-msgpack-numpy
+msgpack-numpy==0.4.1
 html5lib==1.0b8
diff --git a/setup.py b/setup.py
index a588f2c2a..b0f71aa20 100755
--- a/setup.py
+++ b/setup.py
@@ -200,7 +200,7 @@ def setup_package():
                 'regex==2017.4.5',
                 'ftfy>=4.4.2,<5.0.0',
                 'msgpack-python',
-                'msgpack-numpy'],
+                'msgpack-numpy==0.4.1'],
             classifiers=[
                 'Development Status :: 5 - Production/Stable',
                 'Environment :: Console',