diff --git a/.gitignore b/.gitignore
index e78281bc..458c316a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -98,3 +98,4 @@ env3/
 
 # VSCode project settings
 /.vscode
+env2
diff --git a/bin/update_constraints b/bin/update_constraints
index 28ba2077..773a1d83 100755
--- a/bin/update_constraints
+++ b/bin/update_constraints
@@ -14,6 +14,14 @@ subprocess.check_call([
     '--upgrade',
     'cibuildwheel/resources/constraints.in',
 ])
+subprocess.check_call([
+    './env2/bin/pip-compile',
+    '--allow-unsafe',
+    '--generate-hashes',
+    '--upgrade',
+    'cibuildwheel/resources/constraints.in',
+    '--output-file', 'cibuildwheel/resources/constraints-python2.txt'
+])
 
 Image = namedtuple('Image', ['manylinux_version', 'arch'])
 
diff --git a/cibuildwheel/resources/constraints-python2.txt b/cibuildwheel/resources/constraints-python2.txt
new file mode 100644
index 00000000..19b904ee
--- /dev/null
+++ b/cibuildwheel/resources/constraints-python2.txt
@@ -0,0 +1,29 @@
+#
+# This file is autogenerated by pip-compile
+# To update, run:
+#
+#    bin/update_constraints
+#
+auditwheel==2.1.1 \
+    --hash=sha256:d9f0f47c0ecdf4f72316eabfb19223b81aec95f0deba97729e9c09ea4f2c166e \
+    --hash=sha256:f60e265dc168ae7c9d65a814410881c5ca170d88644c178f8e3aa20eecd0fae1
+delocate==0.8.0 \
+    --hash=sha256:ac9f4d8d28b2582d94f764db0d72a1fe3c42ab8212e9b780168455de385d5b95
+pyelftools==0.26 \
+    --hash=sha256:86ac6cee19f6c945e8dedf78c6ee74f1112bd14da5a658d8c9d4103aed5756a2 \
+    --hash=sha256:cc0ea0de82b240a73ef4056fce44acbb4727dca7d66759371aff2bad457ed711 \
+    # via auditwheel
+virtualenv==16.7.9 \
+    --hash=sha256:0d62c70883c0342d59c11d0ddac0d954d0431321a41ab20851facf2b222598f3 \
+    --hash=sha256:55059a7a676e4e19498f1aad09b8313a38fcc0cdbe4fdddc0e9b06946d21b4bb
+wheel==0.31.1 \
+    --hash=sha256:0a2e54558a0628f2145d2fc822137e322412115173e8a2ddbe1c9024338ae83c \
+    --hash=sha256:80044e51ec5bbf6c894ba0bc48d26a8c20a9ba629f4ca19ea26ecfcf87685f5f
+
+# The following packages are considered to be unsafe in a requirements file:
+pip==20.0.2 \
+    --hash=sha256:4ae14a42d8adba3205ebeb38aa68cfc0b6c346e1ae2e699a0b3bad4da19cef5c \
+    --hash=sha256:7db0c8ea4c7ea51c8049640e8e6e7fde949de672bfa4949920675563a5a6967f
+setuptools==44.0.0 \
+    --hash=sha256:180081a244d0888b0065e18206950d603f6550721bd6f8c0a10221ed467dd78e \
+    --hash=sha256:e5baf7723e5bb8382fc146e33032b241efc63314211a3a120aaa55d62d2bb008