diff --git a/eegdash/features/extractors.py b/eegdash/features/extractors.py
index 5df28663..c0bb0759 100644
--- a/eegdash/features/extractors.py
+++ b/eegdash/features/extractors.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
 from collections.abc import Callable
 from functools import partial
diff --git a/eegdash/features/feature_bank/complexity.py b/eegdash/features/feature_bank/complexity.py
index bd29f4c6..3aeef2fb 100644
--- a/eegdash/features/feature_bank/complexity.py
+++ b/eegdash/features/feature_bank/complexity.py
@@ -36,8 +36,12 @@ def preprocess(self, x, m=2, r=0.2, l=1):
         counts_m = np.empty((*x.shape[:-1], (x.shape[-1] - m + 1) // l))
         counts_mp1 = np.empty((*x.shape[:-1], (x.shape[-1] - m) // l))
         for i in np.ndindex(x.shape[:-1]):
-            counts_m[*i, :] = _channel_app_samp_entropy_counts(x[i], m, rr[i], l)
-            counts_mp1[*i, :] = _channel_app_samp_entropy_counts(x[i], m + 1, rr[i], l)
+            counts_m[i + (slice(None),)] = _channel_app_samp_entropy_counts(
+                x[i], m, rr[i], l
+            )
+            counts_mp1[i + (slice(None),)] = _channel_app_samp_entropy_counts(
+                x[i], m + 1, rr[i], l
+            )
         return counts_m, counts_mp1
 
 
@@ -62,7 +66,7 @@ def complexity_sample_entropy(counts_m, counts_mp1):
 def complexity_svd_entropy(x, m=10, tau=1):
     x_emb = np.empty((*x.shape[:-1], (x.shape[-1] - m + 1) // tau, m))
     for i in np.ndindex(x.shape[:-1]):
-        x_emb[*i, :, :] = _create_embedding(x[i], m, tau)
+        x_emb[i + (slice(None), slice(None))] = _create_embedding(x[i], m, tau)
     s = np.linalg.svdvals(x_emb)
     s /= s.sum(axis=-1, keepdims=True)
     return -np.sum(s * np.log(s), axis=-1)
diff --git a/eegdash/features/feature_bank/dimensionality.py b/eegdash/features/feature_bank/dimensionality.py
index 0e8a535a..336744e4 100644
--- a/eegdash/features/feature_bank/dimensionality.py
+++ b/eegdash/features/feature_bank/dimensionality.py
@@ -26,7 +26,7 @@ def dimensionality_higuchi_fractal_dim(x, k_max=10, eps=1e-7):
     for i in np.ndindex(x.shape[:-1]):
         for k in range(1, k_max + 1):
             for m in range(k):
-                L_km[m] = np.mean(np.abs(np.diff(x[*i, m:], n=k)))
+                L_km[m] = np.mean(np.abs(np.diff(x[i + (slice(m, None),)], n=k)))
             L_k[k - 1] = (N - 1) * np.sum(L_km[:k]) / (k**3)
         L_k = np.maximum(L_k, eps)
         hfd[i] = np.linalg.lstsq(log_k, np.log(L_k))[0][0]
diff --git a/eegdash/features/inspect.py b/eegdash/features/inspect.py
index 8e379b58..395a3326 100644
--- a/eegdash/features/inspect.py
+++ b/eegdash/features/inspect.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import inspect
 from collections.abc import Callable
 
diff --git a/eegdash/features/serialization.py b/eegdash/features/serialization.py
index 5aeb1787..75ebdc34 100644
--- a/eegdash/features/serialization.py
+++ b/eegdash/features/serialization.py
@@ -6,6 +6,8 @@
 
 """
 
+from __future__ import annotations
+
 from pathlib import Path
 
 import pandas as pd
diff --git a/tests/test_features.py b/tests/test_features.py
new file mode 100644
index 00000000..8a721ba1
--- /dev/null
+++ b/tests/test_features.py
@@ -0,0 +1,67 @@
+"""Test for features module Python 3.10+ compatibility."""
+
+import pytest
+
+
+def test_import_features_module():
+    """Test that the features module can be imported without syntax errors.
+
+    This test ensures Python 3.10+ compatibility by verifying that:
+    1. Type annotations with list[], type[], and | syntax work (via __future__ imports)
+    2. No Python 3.11+ exclusive syntax is used (like *unpacking in subscripts)
+    """
+    try:
+        import eegdash.features
+
+        assert eegdash.features is not None
+    except SyntaxError as e:
+        pytest.fail(f"SyntaxError when importing eegdash.features: {e}")
+    except ImportError as e:
+        pytest.fail(f"ImportError when importing eegdash.features: {e}")
+
+
+def test_import_features_submodules():
+    """Test that all features submodules can be imported."""
+    submodules = [
+        "eegdash.features.inspect",
+        "eegdash.features.extractors",
+        "eegdash.features.serialization",
+        "eegdash.features.datasets",
+        "eegdash.features.decorators",
+        "eegdash.features.feature_bank",
+        "eegdash.features.feature_bank.complexity",
+        "eegdash.features.feature_bank.dimensionality",
+        "eegdash.features.feature_bank.signal",
+        "eegdash.features.feature_bank.spectral",
+        "eegdash.features.feature_bank.connectivity",
+        "eegdash.features.feature_bank.csp",
+    ]
+
+    for module_name in submodules:
+        try:
+            __import__(module_name)
+        except SyntaxError as e:
+            pytest.fail(f"SyntaxError when importing {module_name}: {e}")
+        except ImportError:
+            # Some imports might fail due to missing dependencies, that's ok
+            # We only care about SyntaxError
+            pass
+
+
+def test_features_basic_functionality():
+    """Test basic features module functionality."""
+    from eegdash.features import (
+        get_all_feature_extractors,
+        get_all_feature_kinds,
+        get_all_features,
+    )
+
+    # These should return lists without errors
+    features = get_all_features()
+    assert isinstance(features, list)
+
+    extractors = get_all_feature_extractors()
+    assert isinstance(extractors, list)
+
+    kinds = get_all_feature_kinds()
+    assert isinstance(kinds, list)