diff --git a/pyproject.toml b/pyproject.toml
index fd01386..76c41b4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,13 +24,13 @@ classifiers = [
 ]
 requires-python = ">=3.12"
 dependencies = [
-    "diffrax>=0.7,<0.8",
+    "diffrax>=0.7.2,<0.8",
     "equinox>=0.12.1,<0.14",
     "interpax>=0.3.13,<0.4",
     "jax>=0.8,<0.12",
     "numpy>=2.4.1,<3",
     "optax>=0.2.4,<0.3",
-    "optimistix>=0.0.10,<0.1",
+    "optimistix>=0.0.10,<0.2",
     "parametrix>=0.1.4,<0.2",
     "scipy>=1.16.1,<2",
 ]
diff --git a/tests/test_neural/test_grenoblesand.py b/tests/test_neural/test_grenoblesand.py
index ee68189..7561036 100644
--- a/tests/test_neural/test_grenoblesand.py
+++ b/tests/test_neural/test_grenoblesand.py
@@ -30,7 +30,7 @@ def test_grenoble_sand() -> None:
 
     # Reference model and nearly saturated boundary forward solution
     D_ref = VanGenuchten(Ks=Ks, alpha=alpha, m=m, theta_range=(0.0, theta_s))
-    ref = frontx.solve(D_ref, i=0, b=theta_s - 1e-7)
+    ref = frontx.solve(D_ref, i=0, b=theta_s - 1e-7, itol=1e-6)
 
     # Trainable model: infer Ks and m from the synthetic reference
     D_train = VanGenuchten(
diff --git a/tests/test_neural/test_validity/test_vangenuchten.py b/tests/test_neural/test_validity/test_vangenuchten.py
index 7ace363..09525b0 100644
--- a/tests/test_neural/test_validity/test_vangenuchten.py
+++ b/tests/test_neural/test_validity/test_vangenuchten.py
@@ -37,4 +37,4 @@ def test_vangenuchten() -> None:
     # Forward re-solve with the fitted D and re-check
     sol2 = frontx.solve(sol.D, i=theta_i, b=theta_b)
     rchisq2 = np.sum((sol2(o) - theta) ** 2 / std**2) / (len(o) - 4)
-    assert rchisq2 <= 2.9
+    assert rchisq2 <= 3