diff --git a/acme/setup.py b/acme/setup.py
index ba2c88394..d2c74accb 100644
--- a/acme/setup.py
+++ b/acme/setup.py
@@ -21,6 +21,7 @@ install_requires = [
 ]
 
 # env markers in extras_require cause problems with older pip: #517
+# Keep in sync with conditional_requirements.py.
 if sys.version_info < (2, 7):
     install_requires.extend([
         # only some distros recognize stdlib argparse as already satisfying
@@ -30,6 +31,7 @@ if sys.version_info < (2, 7):
 else:
     install_requires.append('mock')
 
+# Keep in sync with conditional_requirements.py.
 if sys.version_info < (2, 7, 9):
     # For secure SSL connexion with Python 2.7 (InsecurePlatformWarning)
     install_requires.append('ndg-httpsclient')
diff --git a/letsencrypt_auto/letsencrypt-auto b/letsencrypt_auto/letsencrypt-auto
index 452fb13b4..8ab0e1b95 100755
--- a/letsencrypt_auto/letsencrypt-auto
+++ b/letsencrypt_auto/letsencrypt-auto
@@ -475,13 +475,6 @@ idna==2.0
 # sha256: r2yFz8nNsSuGFlXmufL1lhi_MIjL3oWHJ7LAqY6fZjY
 ipaddress==1.0.15
 
-# sha256: P1c6GL6U3ohtEZHyfBaEJ-9pPo3Pzs-VsXBXey62nLs
-# sha256: HiR9vsxs4FcpnrfuAZrWgxS7kxUugdmmEQ019NXsoPY
-mock==1.3.0
-
-# sha256: 6MFV_evZxLywgQtO0BrhmHVUse4DTddTLXuP2uOKYnQ
-ndg-httpsclient==0.4.0
-
 # sha256: OnTxAPkNZZGDFf5kkHca0gi8PxOv0y01_P5OjQs7gSs
 # sha256: Paa-K-UG9ZzOMuGeMOIBBT4btNB-JWaJGOAPikmtQKs
 parsedatetime==1.5
@@ -513,19 +506,6 @@ pbr==1.8.1
 # sha256: 9QAJM1fQTagUDYeTLKwuVO9ZKlTKinQ6uyhQ9gwsIus
 psutil==3.3.0
 
-# sha256: YfnZnjzvZf6xv-Oi7vepPrk4GdNFv1S81C9OY9UgTa4
-# sha256: GAKm3TIEXkcqQZ2xRBrsq0adM-DSdJ4ZKr3sUhAXJK8
-# sha256: NQJc2UIsllBJEvBOLxX-eTkKhZe0MMLKXQU0z5MJ_6A
-# sha256: L5btWgwynKFiMLMmyhK3Rh7I9l4L4-T5l1FvNr-Co0U
-# sha256: KP7kQheZHPrZ5qC59-PyYEHiHryWYp6U5YXM0F1J-mU
-# sha256: Mm56hUoX-rB2kSBHR2lfj2ktZ0WIo1XEQfsU9mC_Tmg
-# sha256: zaWpBIVwnKZ5XIYFbD5f5yZgKLBeU_HVJ_35OmNlprg
-# sha256: DLKhR0K1Q_3Wj5MaFM44KRhu0rGyJnoGeHOIyWst2b4
-# sha256: UZH_a5Em0sA53Yf4_wJb7SdLrwf6eK-kb1VrGtcmXW4
-# sha256: gyPgNjey0HLMcEEwC6xuxEjDwolQq0A3YDZ4jpoa9ik
-# sha256: hTys2W0fcB3dZ6oD7MBfUYkBNbcmLpInEBEvEqLtKn8
-pyasn1==0.1.9
-
 # sha256: eVm0p0q9wnsxL-0cIebK-TCc4LKeqGtZH9Lpns3yf3M
 pycparser==2.14
 
@@ -609,6 +589,51 @@ letsencrypt==0.1.1
 letsencrypt-apache==0.1.1
 
 UNLIKELY_EOF
+    # -------------------------------------------------------------------------
+    cat << "UNLIKELY_EOF" > "$TEMP_DIR/conditional_requirements.py"
+"""Spit out additional pinned requirements depending on the Python version."""
+from sys import version_info
+
+
+if __name__ == '__main__':
+    if version_info < (2, 7, 9):
+        print """
+# sha256: 6MFV_evZxLywgQtO0BrhmHVUse4DTddTLXuP2uOKYnQ
+ndg-httpsclient==0.4.0
+
+# sha256: YfnZnjzvZf6xv-Oi7vepPrk4GdNFv1S81C9OY9UgTa4
+# sha256: GAKm3TIEXkcqQZ2xRBrsq0adM-DSdJ4ZKr3sUhAXJK8
+# sha256: NQJc2UIsllBJEvBOLxX-eTkKhZe0MMLKXQU0z5MJ_6A
+# sha256: L5btWgwynKFiMLMmyhK3Rh7I9l4L4-T5l1FvNr-Co0U
+# sha256: KP7kQheZHPrZ5qC59-PyYEHiHryWYp6U5YXM0F1J-mU
+# sha256: Mm56hUoX-rB2kSBHR2lfj2ktZ0WIo1XEQfsU9mC_Tmg
+# sha256: zaWpBIVwnKZ5XIYFbD5f5yZgKLBeU_HVJ_35OmNlprg
+# sha256: DLKhR0K1Q_3Wj5MaFM44KRhu0rGyJnoGeHOIyWst2b4
+# sha256: UZH_a5Em0sA53Yf4_wJb7SdLrwf6eK-kb1VrGtcmXW4
+# sha256: gyPgNjey0HLMcEEwC6xuxEjDwolQq0A3YDZ4jpoa9ik
+# sha256: hTys2W0fcB3dZ6oD7MBfUYkBNbcmLpInEBEvEqLtKn8
+pyasn1==0.1.9
+"""
+    if version_info < (2, 7):
+        print """
+# sha256: wxZH7baf09RlqEfqMVfTe-0flfGXYLEaR6qRwEtmYxQ
+# sha256: YrCJpVvh2JSc0rx-DfC9254Cj678jDIDjMhIYq791uQ
+argparse==1.4.0
+
+# sha256: j4MIDaoknQNsvM-4rlzG_wB7iNbZN1ITca-r57Gbrbw
+# sha256: uDndLZwRfHAUMMFJlWkYpCOphjtIsJyQ4wpgE-fS9E8
+mock==1.0.1
+"""
+    else:
+        print """
+# sha256: P1c6GL6U3ohtEZHyfBaEJ-9pPo3Pzs-VsXBXey62nLs
+# sha256: HiR9vsxs4FcpnrfuAZrWgxS7kxUugdmmEQ019NXsoPY
+mock==1.3.0
+"""
+
+UNLIKELY_EOF
+    # -------------------------------------------------------------------------
+    "$VENV_BIN/python" "$TEMP_DIR/conditional_requirements.py" >> "$TEMP_DIR/letsencrypt-auto-requirements.txt"
     # -------------------------------------------------------------------------
     cat << "UNLIKELY_EOF" > "$TEMP_DIR/peep.py"
 #!/usr/bin/env python
diff --git a/letsencrypt_auto/letsencrypt-auto.template b/letsencrypt_auto/letsencrypt-auto.template
index 6e7cf784a..b1852079a 100755
--- a/letsencrypt_auto/letsencrypt-auto.template
+++ b/letsencrypt_auto/letsencrypt-auto.template
@@ -182,6 +182,12 @@ if [ "$1" = "--no-self-upgrade" ]; then
     cat << "UNLIKELY_EOF" > "$TEMP_DIR/letsencrypt-auto-requirements.txt"
 {{ letsencrypt-auto-requirements.txt }}
 UNLIKELY_EOF
+    # -------------------------------------------------------------------------
+    cat << "UNLIKELY_EOF" > "$TEMP_DIR/conditional_requirements.py"
+{{ conditional_requirements.py }}
+UNLIKELY_EOF
+    # -------------------------------------------------------------------------
+    "$VENV_BIN/python" "$TEMP_DIR/conditional_requirements.py" >> "$TEMP_DIR/letsencrypt-auto-requirements.txt"
     # -------------------------------------------------------------------------
     cat << "UNLIKELY_EOF" > "$TEMP_DIR/peep.py"
 {{ peep.py }}
diff --git a/letsencrypt_auto/pieces/conditional_requirements.py b/letsencrypt_auto/pieces/conditional_requirements.py
new file mode 100644
index 000000000..5194a103b
--- /dev/null
+++ b/letsencrypt_auto/pieces/conditional_requirements.py
@@ -0,0 +1,39 @@
+"""Spit out additional pinned requirements depending on the Python version."""
+from sys import version_info
+
+
+if __name__ == '__main__':
+    if version_info < (2, 7, 9):
+        print """
+# sha256: 6MFV_evZxLywgQtO0BrhmHVUse4DTddTLXuP2uOKYnQ
+ndg-httpsclient==0.4.0
+
+# sha256: YfnZnjzvZf6xv-Oi7vepPrk4GdNFv1S81C9OY9UgTa4
+# sha256: GAKm3TIEXkcqQZ2xRBrsq0adM-DSdJ4ZKr3sUhAXJK8
+# sha256: NQJc2UIsllBJEvBOLxX-eTkKhZe0MMLKXQU0z5MJ_6A
+# sha256: L5btWgwynKFiMLMmyhK3Rh7I9l4L4-T5l1FvNr-Co0U
+# sha256: KP7kQheZHPrZ5qC59-PyYEHiHryWYp6U5YXM0F1J-mU
+# sha256: Mm56hUoX-rB2kSBHR2lfj2ktZ0WIo1XEQfsU9mC_Tmg
+# sha256: zaWpBIVwnKZ5XIYFbD5f5yZgKLBeU_HVJ_35OmNlprg
+# sha256: DLKhR0K1Q_3Wj5MaFM44KRhu0rGyJnoGeHOIyWst2b4
+# sha256: UZH_a5Em0sA53Yf4_wJb7SdLrwf6eK-kb1VrGtcmXW4
+# sha256: gyPgNjey0HLMcEEwC6xuxEjDwolQq0A3YDZ4jpoa9ik
+# sha256: hTys2W0fcB3dZ6oD7MBfUYkBNbcmLpInEBEvEqLtKn8
+pyasn1==0.1.9
+"""
+    if version_info < (2, 7):
+        print """
+# sha256: wxZH7baf09RlqEfqMVfTe-0flfGXYLEaR6qRwEtmYxQ
+# sha256: YrCJpVvh2JSc0rx-DfC9254Cj678jDIDjMhIYq791uQ
+argparse==1.4.0
+
+# sha256: j4MIDaoknQNsvM-4rlzG_wB7iNbZN1ITca-r57Gbrbw
+# sha256: uDndLZwRfHAUMMFJlWkYpCOphjtIsJyQ4wpgE-fS9E8
+mock==1.0.1
+"""
+    else:
+        print """
+# sha256: P1c6GL6U3ohtEZHyfBaEJ-9pPo3Pzs-VsXBXey62nLs
+# sha256: HiR9vsxs4FcpnrfuAZrWgxS7kxUugdmmEQ019NXsoPY
+mock==1.3.0
+"""
diff --git a/letsencrypt_auto/pieces/letsencrypt-auto-requirements.txt b/letsencrypt_auto/pieces/letsencrypt-auto-requirements.txt
index 6be690043..5b800b8be 100644
--- a/letsencrypt_auto/pieces/letsencrypt-auto-requirements.txt
+++ b/letsencrypt_auto/pieces/letsencrypt-auto-requirements.txt
@@ -69,13 +69,6 @@ idna==2.0
 # sha256: r2yFz8nNsSuGFlXmufL1lhi_MIjL3oWHJ7LAqY6fZjY
 ipaddress==1.0.15
 
-# sha256: P1c6GL6U3ohtEZHyfBaEJ-9pPo3Pzs-VsXBXey62nLs
-# sha256: HiR9vsxs4FcpnrfuAZrWgxS7kxUugdmmEQ019NXsoPY
-mock==1.3.0
-
-# sha256: 6MFV_evZxLywgQtO0BrhmHVUse4DTddTLXuP2uOKYnQ
-ndg-httpsclient==0.4.0
-
 # sha256: OnTxAPkNZZGDFf5kkHca0gi8PxOv0y01_P5OjQs7gSs
 # sha256: Paa-K-UG9ZzOMuGeMOIBBT4btNB-JWaJGOAPikmtQKs
 parsedatetime==1.5
@@ -107,19 +100,6 @@ pbr==1.8.1
 # sha256: 9QAJM1fQTagUDYeTLKwuVO9ZKlTKinQ6uyhQ9gwsIus
 psutil==3.3.0
 
-# sha256: YfnZnjzvZf6xv-Oi7vepPrk4GdNFv1S81C9OY9UgTa4
-# sha256: GAKm3TIEXkcqQZ2xRBrsq0adM-DSdJ4ZKr3sUhAXJK8
-# sha256: NQJc2UIsllBJEvBOLxX-eTkKhZe0MMLKXQU0z5MJ_6A
-# sha256: L5btWgwynKFiMLMmyhK3Rh7I9l4L4-T5l1FvNr-Co0U
-# sha256: KP7kQheZHPrZ5qC59-PyYEHiHryWYp6U5YXM0F1J-mU
-# sha256: Mm56hUoX-rB2kSBHR2lfj2ktZ0WIo1XEQfsU9mC_Tmg
-# sha256: zaWpBIVwnKZ5XIYFbD5f5yZgKLBeU_HVJ_35OmNlprg
-# sha256: DLKhR0K1Q_3Wj5MaFM44KRhu0rGyJnoGeHOIyWst2b4
-# sha256: UZH_a5Em0sA53Yf4_wJb7SdLrwf6eK-kb1VrGtcmXW4
-# sha256: gyPgNjey0HLMcEEwC6xuxEjDwolQq0A3YDZ4jpoa9ik
-# sha256: hTys2W0fcB3dZ6oD7MBfUYkBNbcmLpInEBEvEqLtKn8
-pyasn1==0.1.9
-
 # sha256: eVm0p0q9wnsxL-0cIebK-TCc4LKeqGtZH9Lpns3yf3M
 pycparser==2.14
 
diff --git a/setup.py b/setup.py
index f95f672ff..494f894d9 100644
--- a/setup.py
+++ b/setup.py
@@ -47,6 +47,7 @@ install_requires = [
 ]
 
 # env markers in extras_require cause problems with older pip: #517
+# Keep in sync with conditional_requirements.py.
 if sys.version_info < (2, 7):
     install_requires.extend([
         # only some distros recognize stdlib argparse as already satisfying