diff --git a/boa/core/solver.py b/boa/core/solver.py
index 7779c7a..a8423d1 100644
--- a/boa/core/solver.py
+++ b/boa/core/solver.py
@@ -4,12 +4,13 @@
 import os
 import tempfile
 
+from boltons.setutils import IndexedSet
+
 from conda.base.constants import ChannelPriority
 from conda.core.solve import diff_for_unlink_link_precs
 from conda.common.serialize import json_dump
 from conda.models.prefix_graph import PrefixGraph
 from conda.core.prefix_data import PrefixData
-from conda._vendor.boltons.setutils import IndexedSet
 from conda.models.match_spec import MatchSpec
 from conda.common.url import remove_auth, split_anaconda_token
 from conda.core.index import _supplement_index_with_system
diff --git a/setup.py b/setup.py
index 28c6dd4..7cf1d86 100644
--- a/setup.py
+++ b/setup.py
@@ -20,6 +20,7 @@
     "prompt-toolkit",
     "joblib",
     "beautifulsoup4",
+    "boltons",
 ]
 
 setup(
diff --git a/tests/env.yml b/tests/env.yml
index cb9dfb5..af0c0db 100644
--- a/tests/env.yml
+++ b/tests/env.yml
@@ -4,6 +4,7 @@ channels:
 dependencies:
   - python>=3.7
   - pip
+  - boltons
   - conda
   - libmambapy >=1.5,<1.6
   - pytest