diff --git a/environment.yml b/environment.yml
index 1af32f750..57d41c004 100644
--- a/environment.yml
+++ b/environment.yml
@@ -11,7 +11,7 @@ dependencies:
   - jaxlib >= 0.4.26
   - jaxlie >= 1.3.0
   - jax-dataclasses >= 1.4.0
-  - optax == 0.2.3
+  - optax >= 0.2.3
   - pptree
   - qpax
   - rod >= 0.3.3
diff --git a/pyproject.toml b/pyproject.toml
index e7d0f5f1d..d2740bf68 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -51,7 +51,7 @@ dependencies = [
     "jaxlie >= 1.3.0",
     "jax_dataclasses >= 1.4.0",
     "pptree",
-    "optax == 0.2.3",
+    "optax >= 0.2.3",
     "qpax",
     "rod >= 0.3.3",
     "typing_extensions ; python_version < '3.12'",
diff --git a/src/jaxsim/rbda/contacts/relaxed_rigid.py b/src/jaxsim/rbda/contacts/relaxed_rigid.py
index f5610bf73..5e20ada54 100644
--- a/src/jaxsim/rbda/contacts/relaxed_rigid.py
+++ b/src/jaxsim/rbda/contacts/relaxed_rigid.py
@@ -182,10 +182,10 @@ class RelaxedRigidContacts(common.ContactModel):
     """Relaxed rigid contacts model."""
 
     _solver_options_keys: jax_dataclasses.Static[tuple[str, ...]] = dataclasses.field(
-        default=("tol", "maxiter", "memory_size"), kw_only=True
+        default=("tol", "maxiter", "memory_size", "scale_init_precond"), kw_only=True
     )
     _solver_options_values: jax_dataclasses.Static[tuple[Any, ...]] = dataclasses.field(
-        default=(1e-6, 50, 10), kw_only=True
+        default=(1e-6, 50, 10, False), kw_only=True
     )
 
     @property