diff --git a/.travis.yml b/.travis.yml
index 6367ce8..613b4f2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,6 +3,7 @@ python:
 - '3.4'
 - '3.5'
 - '3.6'
+# - '3.7'  # Unsupported on Travis
 install:
 - pip install --upgrade pip
 - pip install -e .
diff --git a/mdf_toolbox/toolbox.py b/mdf_toolbox/toolbox.py
index f87d08a..cd0ffa6 100644
--- a/mdf_toolbox/toolbox.py
+++ b/mdf_toolbox/toolbox.py
@@ -10,11 +10,6 @@
 import globus_sdk
 from globus_sdk.base import BaseClient
 from globus_sdk.response import GlobusHTTPResponse
-try:
-    from mdf_connect_client import MDFConnectClient
-except ImportError:
-    print("Proceeding without mdf_connect_client")
-    MDFConnectClient = None
 
 
 KNOWN_SCOPES = {
@@ -45,7 +40,6 @@
     "search": globus_sdk.SearchClient,
     "search_ingest": globus_sdk.SearchClient,
     #  "publish": DataPublicationClient,  # Defined in this module, added to dict later
-    "mdf_connect": MDFConnectClient,
     "groups": NexusClient
 }
 SEARCH_INDEX_UUIDS = {
@@ -950,7 +944,8 @@ def get_local_ep(transfer_client):
 def dict_merge(base, addition):
     """Merge one dictionary with another, recursively.
     Fields present in addition will be added to base.
-    No data in base is deleted or overwritten.
+    No data from base is deleted or overwritten.
+    This function does not modify either dictionary.
 
     Arguments:
     base (dict): The dictionary being added to.
@@ -962,15 +957,16 @@ def dict_merge(base, addition):
     if not isinstance(base, dict) or not isinstance(addition, dict):
         raise TypeError("dict_merge only works with dicts.")
 
+    new_base = deepcopy(base)
     for key, value in addition.items():
         # If the value is a dict, need to merge those
         if isinstance(value, dict):
-            base[key] = dict_merge(base.get(key, {}), value)
+            new_base[key] = dict_merge(new_base.get(key, {}), value)
         # Otherwise, if the key is not in base, add it
-        elif key not in base.keys():
-            base[key] = value
+        elif key not in new_base.keys():
+            new_base[key] = value
 
-    return base
+    return new_base
 
 
 def insensitive_comparison(item1, item2, type_insensitive=False, string_insensitive=False):
diff --git a/setup.py b/setup.py
index 783f56a..76e2845 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 
 setup(
     name='mdf_toolbox',
-    version='0.3.4',
+    version='0.3.5',
     packages=['mdf_toolbox'],
     description='Materials Data Facility Python utilities',
     long_description=("Toolbox is the Materials Data Facility Python package"
diff --git a/tests/test_toolbox.py b/tests/test_toolbox.py
index 4d9199c..6087c90 100644
--- a/tests/test_toolbox.py
+++ b/tests/test_toolbox.py
@@ -36,11 +36,6 @@ def test_login(capsys, monkeypatch):
     assert isinstance(res2.get("publish"), mdf_toolbox.DataPublicationClient)
     assert isinstance(res2.get("groups"), NexusClient)
 
-    creds3 = deepcopy(credentials)
-    creds3["services"] = "mdf_connect"
-    res3 = mdf_toolbox.login(creds3)
-    assert isinstance(res3.get("mdf_connect"), mdf_toolbox.MDFConnectClient)
-
     # Test fetching previous tokens
     creds = deepcopy(credentials)
     assert mdf_toolbox.login(creds).get("petrel_https_server")
@@ -410,7 +405,13 @@ def test_dict_merge():
         }
     }
     # Proper use
+    old_base = deepcopy(base)
+    old_add = deepcopy(add)
     assert mdf_toolbox.dict_merge(base, add) == merged
+    # Originals should be unchanged
+    assert base == old_base
+    assert add == old_add
+
     assert mdf_toolbox.dict_merge({}, {}) == {}
 
     # Check errors