diff --git a/.circleci/config.yml b/.circleci/config.yml
index 2fa4fc556..f90e1d3c6 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -79,7 +79,7 @@ commands:
             docker-compose -f ./.circleci/dcm4chee/auth-docker-compose.yml up -d
             export DICOMWEB_TEST_URL=http://localhost:8008/dcm4chee-arc/aets/DCM4CHEE/rs
             echo "export DICOMWEB_TEST_URL=$DICOMWEB_TEST_URL" >> $BASH_ENV
-            pip install dicomweb_client 'python-keycloak<4.1'
+            pip install dicomweb_client tenacity 'python-keycloak<4.1'
 
             # Wait up to 60 seconds for keycloak to be ready
             echo 'Waiting for keycloak to start...'
diff --git a/.circleci/dcm4chee/docker-compose.yml b/.circleci/dcm4chee/docker-compose.yml
index c25f2e5fb..b81489ac9 100644
--- a/.circleci/dcm4chee/docker-compose.yml
+++ b/.circleci/dcm4chee/docker-compose.yml
@@ -7,7 +7,7 @@ volumes:
   ldap_config: {}
 services:
   ldap:
-    image: dcm4che/slapd-dcm4chee:2.6.6-33.0
+    image: dcm4che/slapd-dcm4chee:2.6.5-31.2
     logging:
       driver: json-file
       options:
@@ -20,7 +20,7 @@ services:
       - ldap_data:/var/lib/openldap/openldap-data
       - ldap_config:/etc/openldap/slapd.d
   db:
-    image: dcm4che/postgres-dcm4chee:16.4-33
+    image: dcm4che/postgres-dcm4chee:15.4-31
     logging:
       driver: json-file
       options:
@@ -34,7 +34,7 @@ services:
     volumes:
       - db_data:/var/lib/postgresql/data
   arc:
-    image: dcm4che/dcm4chee-arc-psql:5.33.0
+    image: dcm4che/dcm4chee-arc-psql:5.31.2
     logging:
       driver: json-file
       options:
diff --git a/.circleci/dcm4chee/upload_example_data.py b/.circleci/dcm4chee/upload_example_data.py
index 80bd308aa..174f51002 100755
--- a/.circleci/dcm4chee/upload_example_data.py
+++ b/.circleci/dcm4chee/upload_example_data.py
@@ -6,6 +6,7 @@
 from dicomweb_client import DICOMwebClient
 from pydicom import dcmread
 from requests import Session
+from tenacity import Retrying, stop_after_attempt, wait_exponential
 
 
 def upload_example_data(server_url, token=None):
@@ -22,8 +23,11 @@ def upload_example_data(server_url, token=None):
 
     datasets = []
     for url in download_urls:
-        resp = urllib.request.urlopen(url)
-        data = resp.read()
+        for attempt in Retrying(stop=stop_after_attempt(5),
+                                wait=wait_exponential(multiplier=1, min=0.5, max=5)):
+            with attempt:
+                resp = urllib.request.urlopen(url)
+                data = resp.read()
         dataset = dcmread(BytesIO(data))
         datasets.append(dataset)
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5772b7d9c..4e568a5b1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 
 - Don't use a default for yaml config files except .large_image_config.yaml ([#1685](../../pull/1685))
 - Some checks for repeated values in the item lists were wrong ([#1686](../../pull/1686))
+- Better support creating zarr sinks from multiple processes ([#1687](../../pull/1687))
 
 ## 1.30.0