diff --git a/HISTORY.txt b/HISTORY.txt
index 441057a0..7914aa67 100644
--- a/HISTORY.txt
+++ b/HISTORY.txt
@@ -1,3 +1,5 @@
+4.0.1:
+ - Pin Sphinx requirement at a Python 2.6 compatible version.
 4.0.0:
  - Make --no-hashes default, introduce --hashes.
  - Fix for key error when uninstalling [dev-]packages
diff --git a/Pipfile b/Pipfile
index 3511fd03..b683ecce 100644
--- a/Pipfile
+++ b/Pipfile
@@ -3,7 +3,7 @@ pytest = "*"
 mock = "*"
 "delegator.py" = ">=0.0.10"
 toml = "*"
-Sphinx = "*"
+Sphinx = "<=1.5.5"
 
 [packages]
 pew = ">=0.1.26"
diff --git a/Pipfile.lock b/Pipfile.lock
index 40a20dde..9683bd0a 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "847845627dfd54f735a83a0bbd6fbef638291e3e8d92e011138c1e2f77d81443"
+            "sha256": "8cba5434b2ba425d05649334b063af088196a5208a5a7c9ae52be9e1467824b8"
         },
         "requires": {
             "python_version": "2.7"
@@ -17,15 +17,9 @@
         "appdirs": {
             "version": "==1.4.3"
         },
-        "backports.shutil_get_terminal_size": {
-            "version": "==1.0.0"
-        },
         "packaging": {
             "version": "==16.8"
         },
-        "pathlib": {
-            "version": "==1.0.1"
-        },
         "pew": {
             "version": "==0.1.26"
         },
@@ -35,12 +29,15 @@
         "pythonz-bd": {
             "version": "==1.11.4"
         },
+        "requests": {
+            "version": "==2.14.2"
+        },
+        "resumable-urlretrieve": {
+            "version": "==0.1.5"
+        },
         "setuptools": {
             "version": "==35.0.2"
         },
-        "shutilwhich": {
-            "version": "==1.1.0"
-        },
         "six": {
             "version": "==1.10.0"
         },
@@ -79,9 +76,6 @@
         "docutils": {
             "version": "==0.13.1"
         },
-        "funcsigs": {
-            "version": "==1.0.2"
-        },
         "imagesize": {
             "version": "==0.7.1"
         },