diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index bab640c5..12c42cd8 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -9,16 +9,16 @@ repos:
       - id: end-of-file-fixer
         exclude_types: [json, binary]
   - repo: https://github.com/psf/black-pre-commit-mirror
-    rev: "25.11.0"
+    rev: "26.1.0"
     hooks:
       - id: black-jupyter
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: "v0.14.7"
+    rev: "v0.15.4"
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]
   - repo: https://github.com/kynan/nbstripout
-    rev: "0.8.2"
+    rev: "0.9.1"
     hooks:
       - id: nbstripout
         exclude: docs/benchmarks.ipynb
diff --git a/pyproject.toml b/pyproject.toml
index 276767e9..d55864ca 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -61,6 +61,7 @@ ignore = [
     "PLR0915", # Allow many statements
     "PLR2004", # Allow magic numbers in comparisons
     "B905",    # Allow zip() without explicit `strict=` parameter
+    "UP047",   # PEP 695 type params require Python 3.12+; project supports 3.11+
 ]
 exclude = []
 
diff --git a/tests/test_gp.py b/tests/test_gp.py
index add8ad91..9268b6ad 100644
--- a/tests/test_gp.py
+++ b/tests/test_gp.py
@@ -25,9 +25,7 @@ def test_sample(data):
     X, _ = data
 
     with jax.enable_x64(True):
-        gp = GaussianProcess(
-            kernels.Matern32(1.5), X, diag=0.01, mean=lambda x: jnp.sum(x)
-        )
+        gp = GaussianProcess(kernels.Matern32(1.5), X, diag=0.01, mean=jnp.sum)
         y = gp.sample(jax.random.PRNGKey(543))
         assert y.shape == (len(X),)