diff --git a/pkgs/development/python-modules/mail-parser/default.nix b/pkgs/development/python-modules/mail-parser/default.nix
index 219a9066dc7..a2e7898f049 100644
--- a/pkgs/development/python-modules/mail-parser/default.nix
+++ b/pkgs/development/python-modules/mail-parser/default.nix
@@ -14,16 +14,6 @@ buildPythonPackage rec {
 
   LC_ALL = "en_US.utf-8";
 
-  # remove version bounds
-  prePatch = ''
-    sed -i -e 's/==.*//g' requirements.txt
-  ''
-  # ipaddress is part of the standard library of Python 3.3+
-  + lib.optionalString (!pythonOlder "3.3") ''
-    substituteInPlace requirements.txt \
-      --replace "ipaddress" ""
-  '';
-
   nativeBuildInputs = [ glibcLocales ];
   propagatedBuildInputs = [ simplejson six ] ++ lib.optional (pythonOlder "3.3") ipaddress;