diff --git a/dev/docker-compose-integration.yml b/dev/docker-compose-integration.yml
index 387e54ac2c..03f5684ce4 100644
--- a/dev/docker-compose-integration.yml
+++ b/dev/docker-compose-integration.yml
@@ -44,7 +44,7 @@ services:
       retries: 5
       start_period: 90s
   rest:
-    image: apache/iceberg-rest-fixture:1.10.1
+    image: apache/iceberg-rest-fixture
     container_name: pyiceberg-rest
     networks:
       iceberg_net:
diff --git a/dev/spark/Dockerfile b/dev/spark/Dockerfile
index 0e1f29d152..e6cba7b589 100644
--- a/dev/spark/Dockerfile
+++ b/dev/spark/Dockerfile
@@ -19,7 +19,7 @@ FROM apache/spark:${BASE_IMAGE_SPARK_VERSION}
 
 # Dependency versions - keep these compatible
 # Changing these will invalidate the JAR download cache layer
-ARG ICEBERG_VERSION=1.10.1
+ARG ICEBERG_VERSION=1.11.0
 ARG ICEBERG_SPARK_RUNTIME_VERSION=4.0_2.13
 ARG HADOOP_VERSION=3.4.1
 ARG AWS_SDK_VERSION=2.24.6
diff --git a/tests/integration/test_catalog.py b/tests/integration/test_catalog.py
index 4188ad83db..b8fddcf3b2 100644
--- a/tests/integration/test_catalog.py
+++ b/tests/integration/test_catalog.py
@@ -670,7 +670,6 @@ def test_rest_drop_view(
 
 
 @pytest.mark.integration
-@pytest.mark.skip(reason="Requires Iceberg REST Fixtures 1.11.x")
 def test_rest_custom_namespace_separator(rest_catalog: RestCatalog, table_schema_simple: Schema) -> None:
     """
     Tests that the REST catalog correctly picks up the namespace-separator from the config endpoint.
@@ -742,19 +741,19 @@ def test_namespace_with_slash(test_catalog: Catalog) -> None:
 
     namespace = ("new/db",)
 
-    if test_catalog.namespace_exists(namespace):
+    if namespace in test_catalog.list_namespaces():
         test_catalog.drop_namespace(namespace)
 
-    assert not test_catalog.namespace_exists(namespace)
+    assert namespace not in test_catalog.list_namespaces()
 
     test_catalog.create_namespace(namespace)
-    assert test_catalog.namespace_exists(namespace)
+    assert namespace in test_catalog.list_namespaces()
 
     properties = test_catalog.load_namespace_properties(namespace)
     assert properties is not None
 
     test_catalog.drop_namespace(namespace)
-    assert not test_catalog.namespace_exists(namespace)
+    assert namespace not in test_catalog.list_namespaces()
 
 
 @pytest.mark.integration