diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 46977e56..c60591b4 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Release
-        uses: patrick-kidger/action_update_python_project@v2
+        uses: patrick-kidger/action_update_python_project@v4
         with:
             python-version: "3.11"
             test-script: |
@@ -21,7 +21,3 @@ jobs:
             pypi-token: ${{ secrets.pypi_token }}
             github-user: patrick-kidger
             github-token: ${{ github.token }}
-            email-user: ${{ secrets.email_user }}
-            email-token: ${{ secrets.email_token }}
-            email-server: ${{ secrets.email_server }}
-            email-target: ${{ secrets.email_target }}
diff --git a/equinox/_ad.py b/equinox/_ad.py
index 2aaac6af..374347e4 100644
--- a/equinox/_ad.py
+++ b/equinox/_ad.py
@@ -878,9 +878,13 @@ def _none_to_zero(ct, x):
         if x is None:
             return None
         else:
-            # No raising-to-vspace. JAX is internally inconsistent, and expects integers
-            # to have integer tangents from custom_{jvp,vjp} rules
-            aval = jax.core.raise_to_shaped(jax.core.get_aval(x))  # .at_least_vspace()
+            aval = jax.core.raise_to_shaped(jax.core.get_aval(x))
+            if hasattr(aval, "to_tangent_aval"):
+                # Earlier versions of JAX were internally inconsistent, and expected
+                # e.g. integer primals to have integer tangents from `custom_{jvp,vjp}`
+                # rules.
+                # That changed in JAX 0.4.34.
+                aval = aval.to_tangent_aval()  # pyright: ignore
             return jax.custom_derivatives.SymbolicZero(aval)
     else:
         return ct
diff --git a/equinox/_jit.py b/equinox/_jit.py
index b1eea161..1d6b190a 100644
--- a/equinox/_jit.py
+++ b/equinox/_jit.py
@@ -110,11 +110,11 @@ def _postprocess(out):
 
 try:
     # Added in JAX 0.4.34.
-    JaxRuntimeError = jax.errors.JaxRuntimeError  # pyright: ignore[reportAttributeAccessIssue]
+    JaxRuntimeError = jax.errors.JaxRuntimeError  # pyright: ignore
 except AttributeError:
     try:
         # Forward compatibility in case they ever decide to fix the capitalization.
-        JaxRuntimeError = jax.errors.JAXRuntimeError  # pyright: ignore[reportAttributeAccessIssue]
+        JaxRuntimeError = jax.errors.JAXRuntimeError  # pyright: ignore
     except AttributeError:
         # Not public API, so wrap in a try-except for forward compatibility.
         try:
diff --git a/equinox/internal/_primitive.py b/equinox/internal/_primitive.py
index 91ffa0e5..c2d63f81 100644
--- a/equinox/internal/_primitive.py
+++ b/equinox/internal/_primitive.py
@@ -59,7 +59,14 @@ def _is_array_like_internal(x):
 
 def _zero_from_primal(p):
     assert type(p) is not ad.UndefinedPrimal
-    return ad.Zero(jax.core.get_aval(p).at_least_vspace())
+    aval = jax.core.get_aval(p)
+    if hasattr(aval, "to_tangent_aval"):
+        # JAX >=0.4.34
+        aval = aval.to_tangent_aval()  # pyright: ignore
+    else:
+        # earlier JAX
+        aval = aval.at_least_vspace()
+    return ad.Zero(aval)
 
 
 def _combine(dynamic, static):