diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 15ea249..0e43b7f 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -15,7 +15,10 @@ jobs:
       with:
         build-artifact-name: none
         build-artifact-path: none
-        pyodide-versions: "0.29.3,0.28.3,0.27.2,0.26.4"
+        # 0.29.4 and 0.29.5 ship a broken coverage wheel (unresolved symbol
+        # MyFrame_BorrowCode in tracer.so) which crashes run_in_pyodide_coverage,
+        # so stay on 0.29.3 for the 0.29.x line.
+        pyodide-versions: "314.0.7,0.29.3,0.28.3,0.27.8,0.26.4"
 
   deploy:
     runs-on: ubuntu-24.04
diff --git a/.github/workflows/testall.yaml b/.github/workflows/testall.yaml
index 0381345..d200805 100644
--- a/.github/workflows/testall.yaml
+++ b/.github/workflows/testall.yaml
@@ -53,7 +53,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - uses: actions/setup-python@42375524e23c412d93fb67b49958b491fce71c38 # v5.4.0
         with:
-          python-version: 3.12 # keep this in sync with Pyodide's Python version
+          python-version: 3.12
       - name: Build test matrix
         id: build-matrix
         run: |
diff --git a/pytest_pyodide/runner.py b/pytest_pyodide/runner.py
index bc48f97..c569682 100644
--- a/pytest_pyodide/runner.py
+++ b/pytest_pyodide/runner.py
@@ -438,8 +438,6 @@ class SeleniumFirefoxRunner(_SeleniumBaseRunner):
     browser = "firefox"
 
     def get_driver(self, jspi=False):
-        if jspi:
-            raise NotImplementedError("JSPI not supported in Firefox")
         from selenium.webdriver import Firefox
         from selenium.webdriver.firefox.options import Options
         from selenium.webdriver.firefox.service import Service
@@ -462,9 +460,6 @@ def get_driver(self, jspi=False):
         options = Options()
         options.add_argument("--headless")
         options.add_argument("--no-sandbox")
-        if jspi:
-            options.add_argument("--enable-features=WebAssemblyExperimentalJSPI")
-            options.add_argument("--enable-experimental-webassembly-features")
         for flag in self._config.get_flags("chrome"):
             options.add_argument(flag)
         return Chrome(options=options)
@@ -662,10 +657,13 @@ def init_node(self, jspi=False):
             )
 
         extra_args = self._config.get_flags("node")[:]
-        # Node v14 require the --experimental-wasm-bigint which
-        # produces errors on later versions
         if jspi:
-            extra_args.append("--experimental-wasm-stack-switching")
+            if node_major <= 21:
+                raise RuntimeError(
+                    f"Node version {node_version} is too old for jspi, please use node >= 22"
+                )
+            if node_major <= 24:
+                extra_args.append("--experimental-wasm-jspi")
 
         self.p.sendline(
             f"node --expose-gc {' '.join(extra_args)} {curdir}/node_test_driver.js {self.base_url} {self.dist_dir}",
diff --git a/tests/test_decorator.py b/tests/test_decorator.py
index 2d479e0..a05a9d9 100644
--- a/tests/test_decorator.py
+++ b/tests/test_decorator.py
@@ -293,22 +293,29 @@ def check_refcount(selenium, n):
 
     import __main__
 
-    assert sys.getrefcount(__main__.o) == n
+    # Don't call getrefcount inside the assert statement: pytest's assertion
+    # rewriting stores subexpressions in temporary locals, which adds an extra
+    # reference on Python <= 3.13 but not on 3.14+ (where locals are pushed to
+    # the stack as borrowed references).
+    refcount = sys.getrefcount(__main__.o)
+    assert refcount == n
 
 
 def test_selenium_handle(selenium):
     handle = returns_handle(selenium)
-    check_refcount(selenium, 4)
+    # References to __main__.o: the __main__ module dict, the _Py_IncRef done
+    # when the PyodideHandle was pickled, and the getrefcount argument.
+    check_refcount(selenium, 3)
     set_handle(selenium, handle, 7, 2)
     set_handle(selenium, handle, "b", 1)
     assert_get_handle(selenium, handle, "a", 6)
     assert_get_handle(selenium, handle, 7, 2)
     assert_get_handle(selenium, handle, "b", 1)
-    check_refcount(selenium, 4)
+    check_refcount(selenium, 3)
 
     # FIXME: refcount not decremented when deleting handle
     del handle
-    # check_refcount(selenium, 3)
+    # check_refcount(selenium, 2)
 
 
 def test_pytest_dot_skip(selenium):
diff --git a/tests/test_fixture.py b/tests/test_fixture.py
index 0200740..351ce11 100644
--- a/tests/test_fixture.py
+++ b/tests/test_fixture.py
@@ -33,7 +33,7 @@ def test_playwright_browsers(playwright_browsers, request):
 def test_jspi(selenium_jspi):
     from js import WebAssembly
 
-    assert hasattr(WebAssembly, "Suspender")
+    assert hasattr(WebAssembly, "Suspending")
 
 
 @run_in_pyodide
diff --git a/utils/build_test_matrix.py b/utils/build_test_matrix.py
index a874f16..598302d 100644
--- a/utils/build_test_matrix.py
+++ b/utils/build_test_matrix.py
@@ -12,9 +12,9 @@
 DEFAULT_BROWSER = "chrome, firefox, node, safari, host"
 # at the time of writing, chrome latest (>131) times out.
 # xref: https://github.com/pyodide/pytest-pyodide/pull/146
-DEFAULT_CHROME_VERSION = "125"
+DEFAULT_CHROME_VERSION = "153"
 DEFAULT_FIREFOX_VERSION = "latest"
-DEFAULT_NODE_VERSION = "22"
+DEFAULT_NODE_VERSION = "26"
 DEFAULT_PLAYWRIGHT_VERSION = "1.44.0"
 
 
@@ -33,6 +33,10 @@ class VersionPair:
 
 def python_version_for_pyodide(pyodide_version: str) -> str:
     pyodide_ver = tuple(int(x) for x in pyodide_version.split(".")[:2])
+    if pyodide_ver[0] > 0:
+        minor = str(pyodide_ver[0])[1:]
+        return f"3.{minor}"
+
     for pair in PYODIDE_TO_PYTHON_VERSION:
         if pyodide_ver >= pair.pyodide_version:
             return pair.python_version