diff --git a/binstar_client/__init__.py b/binstar_client/__init__.py
index e76bdf95..5dff7d6a 100644
--- a/binstar_client/__init__.py
+++ b/binstar_client/__init__.py
@@ -13,7 +13,6 @@
 
 import defusedxml.ElementTree as ET
 import requests
-from pkg_resources import parse_version as pv
 from tqdm import tqdm
 
 from . import errors
@@ -186,15 +185,6 @@ def remove_authentication(self, auth_name=None, organization=None):
 
     def _check_response(self, res, allowed=None):
         allowed = [200] if allowed is None else allowed
-        api_version = res.headers.get('x-binstar-api-version', '0.2.1')
-        if pv(api_version) > pv(__version__):
-            # pylint: disable=implicit-str-concat
-            logger.warning(
-                'The api server is running the binstar-api version %s. you are using %s\n'
-                'Please update your client with pip install -U binstar or conda update binstar',
-                api_version,
-                __version__,
-            )
 
         if not self._token_warning_sent and 'Conda-Token-Warning' in res.headers:
             logger.warning('Token warning: %s', res.headers['Conda-Token-Warning'])
diff --git a/binstar_client/inspect_package/pypi.py b/binstar_client/inspect_package/pypi.py
index ace0ed7e..536ab07e 100644
--- a/binstar_client/inspect_package/pypi.py
+++ b/binstar_client/inspect_package/pypi.py
@@ -11,7 +11,7 @@
 from email.parser import Parser
 from os import path
 
-import pkg_resources
+from packaging.requirements import Requirement
 
 from binstar_client import errors
 from binstar_client.inspect_package.uitls import extract_first, pop_key
@@ -145,12 +145,19 @@ def python_version_check(filedata):
 
 
 def parse_requirement(line, deps, extras, extra):
-    req = pkg_resources.Requirement.parse(line)
-    req.specs.sort(key=sort_ver)
+    parsed_req = Requirement(line)
+    name = parsed_req.name.lower()
+    specs = sorted(
+        (
+            (spec.operator, spec.version) for spec in parsed_req.specifier
+        ),
+        key=sort_ver,
+    )
+
     if extra:
-        extras[extra].append({'name': req.key, 'specs': req.specs or []})
+        extras[extra].append({'name': name, 'specs': specs})
     else:
-        deps.append({'name': req.key, 'specs': req.specs or []})
+        deps.append({'name': name, 'specs': specs})
 
     deps.sort(key=sort_key)
     for extra_item in extras.values():
@@ -197,37 +204,18 @@ def parse_requires_txt(requires_txt):
 def format_requirements(requires):
     obj = []
     for req in requires:
-        req = req.strip()
-
-        # Get environment marker
-        marker = None
-        if ';' in req:
-            req, marker = req.split(';', 1)
-            marker = marker.strip()
-        else:
-            marker = None
-
-        req_spec = req.split(' ', 1)
-        if len(req_spec) == 1:
-            # Note: req.lower() was introduced here to enforce the same parsing
-            # using metadata.json and METADATA
-            obj.append({'name': req.lower(), 'specs': []})
-        else:
-            req, spec = req_spec
-            spec = spec.strip()
-
-            if spec[0] == '(':
-                spec = spec[1:]
-
-            if spec[-1] == ')':
-                spec = spec[:-1]
-
-            req = pkg_resources.Requirement.parse('%s %s' % (req, spec))
-            req.specs.sort(key=sort_ver)
-            obj.append({
-                'name': req.key,
-                'specs': req.specs or [],
-            })
+        parsed_req = Requirement(req)
+        name = parsed_req.name.lower()
+        specs = sorted(
+            (
+                (spec.operator, spec.version) for spec in parsed_req.specifier
+            ),
+            key=sort_ver,
+        )
+        obj.append({
+            'name': name,
+            'specs': specs,
+        })
     return obj
 
 
diff --git a/setup.cfg b/setup.cfg
index d371c9b6..687354f7 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -179,3 +179,6 @@ redefining-builtins-modules=past.builtins,future.builtins,builtins,io
 [tool:pytest]
 addopts=--durations 10 --cov=binstar_client --cov-report term-missing
 cache_dir=.cache/pytest
+# Treat all warnings errors: https://til.simonwillison.net/pytest/treat-warnings-as-errors
+filterwarnings =
+    error