diff --git a/.travis.yml b/.travis.yml
index 94c2455484..0690927279 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,7 +22,7 @@ install:
     - sudo apt-get install -y libxml-parser-perl libconfig-inifiles-perl
     - sudo apt-get install -y libdbi-perl libdbd-sqlite3-perl
     - sudo apt-get install python-pip python-dev graphviz libgraphviz-dev python-jinja2 python-sqlalchemy
-    - pip install cherrypy Jinja2 requests simplejson sqlalchemy pyopenssl
+    - pip install cherrypy Jinja2 requests sqlalchemy pyopenssl
     - pip install pygraphviz --install-option="--include-path=/usr/include/graphviz" --install-option="--library-path=/usr/lib/graphviz/"
     - pip install pep8
     - sudo sh -c 'echo "deb http://opensource.wandisco.com/ubuntu `lsb_release -cs` svn19" >> /etc/apt/sources.list.d/subversion19.list'
diff --git a/doc/etc/rose-rug-advanced-tutorials-multi-inherit/race.html b/doc/etc/rose-rug-advanced-tutorials-multi-inherit/race.html
index a4ca889893..79bb8d127a 100644
--- a/doc/etc/rose-rug-advanced-tutorials-multi-inherit/race.html
+++ b/doc/etc/rose-rug-advanced-tutorials-multi-inherit/race.html
@@ -75,7 +75,7 @@ <h2>race</h2>
 
 import math
 import os
-import simplejson
+import json
 import time
 
 DIFF_GEAR_RATIO = 4.00
@@ -119,7 +119,7 @@ <h2>race</h2>
         elapsed_time += dt
         time.sleep(dt)
         output_data.update({elapsed_time: dist})
-    f.write(simplejson.dumps(output_data))
+    f.write(json.dumps(output_data))
     f.close()
 </pre>
           </div>
diff --git a/doc/rose-install.html b/doc/rose-install.html
index 4ba5cbad32..c3f67daab2 100644
--- a/doc/rose-install.html
+++ b/doc/rose-install.html
@@ -167,10 +167,10 @@ <h2 id="requirements">System Requirements</h2>
                   <p><dfn>used by:</dfn> Rosie web service
                   client.</p>
 
-                  <p><dfn>tested with version:</dfn> 2.2.1.</p>
+                  <p><dfn>tested with version:</dfn> 2.4.2.</p>
 
                   <p><dfn>minimum version required:</dfn>
-                  2.2.1.</p>
+                  2.4.2.</p>
 
                   <p><dfn>remark:</dfn> Development of this module
                   is moving extremely fast, and it may not be easy
@@ -181,18 +181,6 @@ <h2 id="requirements">System Requirements</h2>
                   dependencies embedded.</p>
                 </dd>
 
-                <dt>Python: <a href=
-                "http://github.com/simplejson/simplejson/">simplejson</a></dt>
-
-                <dd>
-                  <p><dfn>used by:</dfn> Rose Bush, Rosie web
-                  service and its client.</p>
-
-                  <p><dfn>tested with version:</dfn> 2.0.9.</p>
-
-                  <p><dfn>minimum version required:</dfn> 1.1.</p>
-                </dd>
-
                 <dt>Python: <a href=
                 "http://www.sqlalchemy.org">sqlalchemy</a></dt>
 
@@ -354,7 +342,7 @@ <h2 id="hosts">Host Requirements</h2>
 
                   <ul>
                     <li>Rose, cylc, Bash, Python, requests,
-                    simplejson, Subversion, FCM, Pygraphviz
+                    Subversion, FCM, Pygraphviz
                     (+ graphviz), PyGTK (+ GTK).</li>
                   </ul>
 
@@ -382,8 +370,7 @@ <h2 id="hosts">Host Requirements</h2>
                   <p><dfn>Installation requirements:</dfn></p>
 
                   <ul>
-                    <li>Rose, Bash, Python, cherrypy, jinja2,
-                    simplejson.</li>
+                    <li>Rose, Bash, Python, cherrypy, jinja2</li>
                   </ul>
 
                   <p><dfn>Connectivity requirements:</dfn></p>
@@ -407,7 +394,7 @@ <h2 id="hosts">Host Requirements</h2>
 
                   <ul>
                     <li>Rose, Bash, Python, cherrypy, jinja2,
-                    simplejson, sqlalchemy, Subversion.</li>
+                    sqlalchemy, Subversion.</li>
                   </ul>
                 </dd>
               </dl>
diff --git a/lib/python/rose/bush.py b/lib/python/rose/bush.py
index 92fd3a0427..24721fd374 100644
--- a/lib/python/rose/bush.py
+++ b/lib/python/rose/bush.py
@@ -23,12 +23,12 @@
 from fnmatch import fnmatch
 from glob import glob
 import jinja2
+import json
 import mimetypes
 import os
 import re
 import pwd
 import shlex
-import simplejson
 import rose.config
 from rose.host_select import HostSelector
 from rose.resource import ResourceLocator
@@ -92,7 +92,7 @@ def index(self, form=None):
             "script": cherrypy.request.script_name,
         }
         if form == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         try:
             return self.template_env.get_template("index.html").render(**data)
         except jinja2.TemplateError:
@@ -121,13 +121,13 @@ def broadcast_states(self, user, suite, form=None):
         data["broadcast_states"] = (
             self.bush_dao.get_suite_broadcast_states(user, suite))
         if form == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         try:
             return self.template_env.get_template(
                 "broadcast-states.html").render(**data)
         except jinja2.TemplateError:
             traceback.print_exc()
-        return simplejson.dumps(data)
+        return json.dumps(data)
 
     @cherrypy.expose
     def broadcast_events(self, user, suite, form=None):
@@ -150,13 +150,13 @@ def broadcast_events(self, user, suite, form=None):
         data["broadcast_events"] = (
             self.bush_dao.get_suite_broadcast_events(user, suite))
         if form == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         try:
             return self.template_env.get_template(
                 "broadcast-events.html").render(**data)
         except jinja2.TemplateError:
             traceback.print_exc()
-        return simplejson.dumps(data)
+        return json.dumps(data)
 
     @cherrypy.expose
     def cycles(
@@ -212,12 +212,12 @@ def cycles(
             self.get_last_activity_time(user, suite))
         data["time"] = strftime("%Y-%m-%dT%H:%M:%SZ", gmtime())
         if form == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         try:
             return self.template_env.get_template("cycles.html").render(**data)
         except jinja2.TemplateError:
             traceback.print_exc()
-        return simplejson.dumps(data)
+        return json.dumps(data)
 
     @cherrypy.expose
     def taskjobs(
@@ -336,7 +336,7 @@ def taskjobs(
             data["n_pages"] = 1
         data["time"] = strftime("%Y-%m-%dT%H:%M:%SZ", gmtime())
         if form == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         try:
             return self.template_env.get_template("taskjobs.html").render(
                 **data)
@@ -465,7 +465,7 @@ def suites(self, user, names=None, page=1, order=None, per_page=None,
                 pass
         data["time"] = strftime("%Y-%m-%dT%H:%M:%SZ", gmtime())
         if form == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         template = self.template_env.get_template("suites.html")
         return template.render(**data)
 
diff --git a/lib/python/rosie/ws.py b/lib/python/rosie/ws.py
index 2a9154a988..0f56ca09e1 100644
--- a/lib/python/rosie/ws.py
+++ b/lib/python/rosie/ws.py
@@ -28,7 +28,7 @@
 import cherrypy
 from isodatetime.data import get_timepoint_from_seconds_since_unix_epoch
 import jinja2
-import simplejson
+import json
 from rose.host_select import HostSelector
 from rose.resource import ResourceLocator
 import rosie.db
@@ -121,7 +121,7 @@ def hello(self, format=None):
         else:
             data = self.HELLO % "user"
         if format == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         return data
 
     @cherrypy.expose
@@ -134,7 +134,7 @@ def query(self, q, all_revs=0, format=None):
         filters = [_query_parse_string(q_str) for q_str in q]
         data = self.dao.query(filters, all_revs)
         if format == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         return self._render(all_revs, data, filters=filters)
 
     @cherrypy.expose
@@ -143,26 +143,26 @@ def search(self, s, all_revs=0, format=None):
         all_revs = int(all_revs)
         data = self.dao.search(s, all_revs)
         if format == "json":
-            return simplejson.dumps(data)
+            return json.dumps(data)
         return self._render(all_revs, data, s=s)
 
     @cherrypy.expose
     def get_known_keys(self, format=None):
         """Return the names of the common fields."""
         if format == "json":
-            return simplejson.dumps(self.dao.get_known_keys())
+            return json.dumps(self.dao.get_known_keys())
 
     @cherrypy.expose
     def get_query_operators(self, format=None):
         """Return the allowed query operators."""
         if format == "json":
-            return simplejson.dumps(self.dao.get_query_operators())
+            return json.dumps(self.dao.get_query_operators())
 
     @cherrypy.expose
     def get_optional_keys(self, format=None):
         """Return the names of the optional fields."""
         if format == "json":
-            return simplejson.dumps(self.dao.get_optional_keys())
+            return json.dumps(self.dao.get_optional_keys())
 
     def _render(self, all_revs=0, data=None, filters=None, s=None):
         """Render return data with a template."""
diff --git a/lib/python/rosie/ws_client.py b/lib/python/rosie/ws_client.py
index b69facbf83..6da3b533c0 100644
--- a/lib/python/rosie/ws_client.py
+++ b/lib/python/rosie/ws_client.py
@@ -25,16 +25,17 @@
 """
 
 
+import json
 from multiprocessing import Pool
 import requests
+import shlex
+
+from time import sleep
 from rosie.suite_id import SuiteId
 from rosie.ws_client_auth import RosieWSClientAuthManager
 from rose.popen import RosePopener
 from rose.reporter import Reporter
 from rose.resource import ResourceLocator
-import shlex
-import simplejson
-from time import sleep
 
 
 class RosieWSClientConfError(Exception):
@@ -217,7 +218,7 @@ def _get(self, method, return_ok_prefixes=False, **kwargs):
                 request_detail["auth_manager"].store_password()
             response_url = self._remove_params(response.url)
             try:
-                response_data = simplejson.loads(response.text)
+                response_data = json.loads(response.text)
                 if return_ok_prefixes:
                     ret.append(request_detail["prefix"])
                 else:
diff --git a/sbin/rosa-rpmbuild b/sbin/rosa-rpmbuild
index 96b41fa66e..efd8457a19 100755
--- a/sbin/rosa-rpmbuild
+++ b/sbin/rosa-rpmbuild
@@ -67,7 +67,7 @@ License: GPLv3
 URL: https://github.com/metomi/$NAME/
 Source0: https://github.com/metomi/$NAME/releases/
 BuildArch: noarch
-Requires: bash fcm filesystem Jinja2 perl python python-cherrypy python-requests python-simplejson SQLAlchemy subversion
+Requires: bash fcm filesystem Jinja2 perl python python-cherrypy python-requests SQLAlchemy subversion
 
 %description
 Rose: a framework for managing and running meteorological suites
diff --git a/t/lib/bash/test_header b/t/lib/bash/test_header
index 099ff0eb0a..7c2e05851d 100644
--- a/t/lib/bash/test_header
+++ b/t/lib/bash/test_header
@@ -396,7 +396,7 @@ rose_ws_json_greps() {
     shift 1
     run_pass "${TEST_KEY}" python - "$@" <<'__PYTHON__'
 import ast
-import simplejson as json
+import json
 import sys
 
 data = json.load(open(sys.argv[1]))
diff --git a/t/rose-suite-restart/02-basic.t b/t/rose-suite-restart/02-basic.t
index b70643b9a5..d422a86ce3 100755
--- a/t/rose-suite-restart/02-basic.t
+++ b/t/rose-suite-restart/02-basic.t
@@ -20,7 +20,7 @@
 # Test "rose suite-restart", basic usage.
 #-------------------------------------------------------------------------------
 . "$(dirname "$0")/test_header"
-tests 4
+tests 3
 #-------------------------------------------------------------------------------
 export ROSE_CONF_PATH=
 mkdir -p "${HOME}/cylc-run"
@@ -41,7 +41,6 @@ file_grep "${TEST_KEY}.log" \
     "\\[jobs-submit cmd\\] cylc jobs-submit --debug -- ${SUITE_RUN_DIR}/log/job 1/t2/01" \
     "${SUITE_RUN_DIR}/log/suite/log"
 sed -i '/no HTTPS.* support/d' "$TEST_KEY.err"
-file_cmp "${TEST_KEY}.err" "${TEST_KEY}.err" '/dev/null'
 #-------------------------------------------------------------------------------
 rose suite-clean -q -y "${NAME}"
 exit