diff --git a/docs/conf.py b/docs/conf.py
index 0e94e2da..0059b5e6 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -14,8 +14,8 @@
 
 
 project = "numbox"
-copyright = "2025, Mikhail Goykhman"
-author = "Mikhail Goykhman"
+copyright = "2026, NumbOx GitHub Repository Contributors"
+author = "NumbOx GitHub Repository Contributors"
 
 # -- General configuration ---------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
diff --git a/docs/numbox.core.proxy.rst b/docs/numbox.core.proxy.rst
index 325688fd..ad355e90 100644
--- a/docs/numbox.core.proxy.rst
+++ b/docs/numbox.core.proxy.rst
@@ -56,8 +56,9 @@ with the rest.
 From numba 0.61 onward ``.as_func`` inherits the mixed-container limit of any
 derive value: a tuple holding it alongside a plain ``CompileResultWAP`` no longer
 unifies, failing with a message-less ``AssertionError`` from
-``numba.core.utils.unified_function_type``. See :doc:`numbox.core.work` for that
-limit and for why making the two types compare equal is not available as a fix.
+``numba.core.utils.unified_function_type`` (fixed in numba==0.68.0).
+See :doc:`numbox.core.work` for that limit and for why making the two types
+compare equal is not available as a fix.
 
 Referencing ``.as_func`` as a constant carries a caching caveat that passing it
 as a function-type argument does not; read `Cache invalidation`_ below before
diff --git a/docs/numbox.core.work.rst b/docs/numbox.core.work.rst
index 81b0d16e..787475b3 100644
--- a/docs/numbox.core.work.rst
+++ b/docs/numbox.core.work.rst
@@ -591,20 +591,21 @@ These limits are worth knowing:
 - A container that mixes a `cres` derive with a differently typed function value: a tuple
   holding a `cres` alongside a plain ``CompileResultWAP``, a signature-declared njit
   dispatcher or a ``cfunc``. numba unifies the element types before any of numbox's
-  conversions apply, and ``numba.core.utils.unified_function_type`` requires every
-  function type it meets to equal the first through a bare ``assert``, so the failure
-  arrives as an ``AssertionError`` carrying no message. A lazily compiled ``@njit``
-  dispatcher in the mix is the one subcase that reads differently: unification accepts
-  it, and numbox's guard then rejects it at the unboxing boundary with a ``TypeError``
-  naming the offending type.
+  conversions apply, and ``numba.core.utils.unified_function_type``, for numba<0.68.0,
+  requires every function type it meets to equal the first through a bare ``assert``,
+  so the failure arrives as an ``AssertionError`` carrying no message (fixed in numba==0.68.0).
+  A lazily compiled ``@njit`` dispatcher in the mix is the one subcase that reads
+  differently: unification accepts it, and numbox's guard then rejects it at the unboxing
+  boundary with a ``TypeError`` naming the offending type.
   From numba 0.61 onward a ``@proxy`` binding's ``.as_func`` is a `DeriveFunctionType`
   value as well (see :doc:`numbox.core.proxy`), so it meets this limit identically: a
-  tuple mixing it with a plain ``CompileResultWAP`` fails on the same assertion, where
-  before it unified and returned a value.
+  tuple mixing it with a plain ``CompileResultWAP`` fails on the same assertion, for numba<0.68,
+  where before it unified and returned a value.
   Homogeneous containers are unaffected, including a tuple of two `cres` derives, or a
   `cres` derive alongside a `@proxy` binding's `.as_func` of the same signature. This
   is not specific to numbox: two plain ``CompileResultWAP`` values of different
-  signatures but the same argument count fail identically with numbox uninvolved.
+  signatures but the same argument count fail identically with numbox uninvolved,
+  for numba<0.68.
   What numbox changes is how easily the case is reached, since `DeriveFunctionType` is a
   distinct type from ``FunctionType`` and numba compares function types by class. Making the
   two compare equal is not available as a fix. numba interns types in a cache keyed by a
diff --git a/numbox/core/configurations.py b/numbox/core/configurations.py
index 8c9f5dfc..375dac44 100644
--- a/numbox/core/configurations.py
+++ b/numbox/core/configurations.py
@@ -18,6 +18,10 @@
 from numba.core.types import FunctionType, void
 
 
+numba_version = int(version("numba").split(".")[1])
+assert numba_version >= 60, numba_version
+
+
 def get_jit_options():
     """
     E.g., export NUMBOX_JIT_OPTIONS='{"cache": false}'
@@ -87,17 +91,22 @@ def check_cache_location(py_file, longest_file_name=0):
 
 
 def is_a_cache_error(error):
-    """Whether ``error`` is numba's for a cache it cannot set up: no locator, or a location it cannot use.
+    """Whether ``error`` is numba's for a cache it cannot set up: no locator, a location it cannot use, or
+    missing source files(s) on numba>=0.68.
 
     numba itself passes over a location on any ``OSError`` from making its directory or writing a file there,
     permission denied, a read-only file system, a path into a file, a component too long, a full disk, so any
     ``OSError`` counts. So does the ``ValueError`` numba raises for an archive under a directory whose name
     holds ``.zip``: its ``.zip`` locator takes the file by that substring and then finds no ``.zip`` in it.
+    numba>=0.68 started hashing the source contents of the archive into the archive's cache stamp, therefore
+    missing .py raise KeyError.
     """
     if isinstance(error, OSError):
         return True
     if isinstance(error, ValueError):
         return "No zip file found" in str(error)
+    if isinstance(error, KeyError):
+        return numba_version >= 68 and "There is no item named" in str(error)
     return isinstance(error, RuntimeError) and "no locator available" in str(error)
 
 
@@ -237,6 +246,14 @@ def cache_remedy(py_file, failure, silence, package="numbox"):
     files on disk: a package built on numbox that puts the question for its own files with
     ``check_cache_location`` and ``is_a_cache_error`` passes its own name, as it passes ``check_cache_location`` a
     ``longest_file_name`` for its own functions, ``LONGEST_CACHE_FILE_NAME`` being numbox's.
+
+    On numba==0.68.0, ``KeyError`` caused by the Windows ZIP path separator
+    bug https://github.com/numba/numba/issues/10889 can be worked around by
+    disabling caching. The bug is scheduled to be fixed in 0.68.1.
+
+    On numba>=0.68, ``KeyError`` caused by missing .py source files in the ZIP
+    archive (when only compiled `.pyc` files are present) can be avoided by either
+    disabling caching or including all source files in the archive.
     """
     if os.path.exists(py_file):
         if isinstance(failure, OSError) and failure.errno == errno.ENAMETOOLONG:
@@ -249,18 +266,37 @@ def cache_remedy(py_file, failure, silence, package="numbox"):
         # numba itself passes a location it cannot make or write over, for a
         # source on disk, so the error here is the no-locator one.
         return f"Set NUMBA_CACHE_DIR to a writable directory, or {silence}"
+    if isinstance(failure, KeyError):
+        if "\\" in str(failure) and os.name == "nt":
+            return (
+                "Numba 0.68's ZIP cache locator uses Windows path separators for ZIP members, "
+                "see https://github.com/numba/numba/issues/10889"
+            )
+        return f"For numba>=0.68, put all source .py file(s) in .zip, or {silence}"
     if isinstance(failure, OSError) or getattr(sys, "frozen", False):
         # The .zip's error names the location numba picked, which is under
         # the user's cache directory; the frozen application's names nothing.
         location = getattr(failure, "filename", None) or AppDirs(appname="numba", appauthor=False).user_cache_dir
+        if (
+            isinstance(failure, OSError)
+            and failure.errno == errno.EISDIR and location and location.endswith(".zip")
+            and os.path.isdir(location) and py_file.startswith(location + os.sep)
+        ):
+            return (
+                f"the path {location} is a directory whose name ends in .zip, "
+                "which numba mistakes for the source archive; rename that "
+                "directory, or use a path without a .zip-named directory, "
+                f"or {silence}"
+            )
         if isinstance(failure, FileNotFoundError) and py_file.startswith(failure.filename + os.sep):
             # The stamp numba reads at decoration, of the archive the code
             # names: .pyc members compiled to name an archive since moved. A
             # location that cannot be made, under a dangling link, is ENOENT
             # too, and is not under the code's file.
+            suggestion = "" if numba_version >= 68 else "compile the archive's .pyc members to name its path now, or "
             return (
                 f"the module's code names {failure.filename}, which is not there: its .pyc was compiled to name "
-                "that path, so compile the archive's .pyc members to name its path now, or ship its source files; "
+                f"that path, {suggestion}ship its source files; "
                 f"or {silence}"
             )
         if isinstance(failure, OSError) and failure.errno == errno.ENAMETOOLONG:
@@ -316,7 +352,7 @@ def uncached_where_no_cache_can_be_written(options):
     for py_file in _module_files():
         try:
             check_cache_location(py_file, LONGEST_CACHE_FILE_NAME)
-        except (RuntimeError, OSError, ValueError) as error:
+        except (RuntimeError, OSError, KeyError, ValueError) as error:
             if not is_a_cache_error(error):
                 raise
             failure = error
@@ -356,10 +392,6 @@ def _strict_cache_mode():
 
 MAX_STR_LENGTH = 2 ** 31 - 1
 
-
-numba_version = int(version("numba").split(".")[1])
-assert numba_version >= 60, numba_version
-
 #: numba's `FunctionModel`, resolved once. Looking a data model up is type machinery and
 #: compiles nothing, which is what lets the layout be read here: `numbox.utils.lowlevel` and
 #: `numbox.utils.derive_wap` both need it on paths that must stay free of compilation side
diff --git a/numbox/core/variable/variable.py b/numbox/core/variable/variable.py
index a9c05bc1..e763ba89 100644
--- a/numbox/core/variable/variable.py
+++ b/numbox/core/variable/variable.py
@@ -385,7 +385,7 @@ def _calculate(self, nodes: list[CompiledNode], values: Storage):
                     raise RuntimeError(f"Uninitialized input {input_.qual_name()} for {node.variable}")
                 args[i] = arg
             if self.debug:
-                print(f"Calculating {node}\nwith metadata\n{node.variable.metadata}", file=sys.stderr)
+                print(f"Calculating {node}\nwith metadata\n{node.variable.metadata}", file=sys.stderr, flush=True)
             result = node.variable.formula(*args)
             values.get(node.variable).value = result
 
diff --git a/numbox/utils/preprocessing.py b/numbox/utils/preprocessing.py
index fad4bbea..faf671e2 100644
--- a/numbox/utils/preprocessing.py
+++ b/numbox/utils/preprocessing.py
@@ -155,7 +155,7 @@ def _cached_at_or_uncached(py_file: str, jit_options: dict) -> dict:
         return jit_options
     try:
         check_cache_location(py_file, LONGEST_CACHE_FILE_NAME)
-    except (RuntimeError, OSError, ValueError) as error:
+    except (RuntimeError, OSError, KeyError, ValueError) as error:
         if not is_a_cache_error(error):
             raise
         failure = error
diff --git a/pyproject.toml b/pyproject.toml
index f9c75e3f..d06285b9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ include = ["numbox*"]
 [project]
 name = "numbox"
 dependencies = [
-    "numba>=0.60.0,<0.68.0"
+    "numba>=0.60.0,<0.69.0"
 ]
 dynamic = ["version"]
 requires-python = ">=3.10"
diff --git a/test/core/test_no_cache_location.py b/test/core/test_no_cache_location.py
index 29b5c49b..86601a1f 100644
--- a/test/core/test_no_cache_location.py
+++ b/test/core/test_no_cache_location.py
@@ -13,6 +13,7 @@
 import marshal
 import os
 import py_compile
+import pytest
 import re
 import shutil
 import subprocess
@@ -20,7 +21,6 @@
 import zipfile
 from pathlib import Path
 
-import pytest
 
 REPO = Path(__file__).resolve().parent.parent.parent
 
@@ -130,6 +130,9 @@ def test_options_without_a_cache_key_are_asked_for_the_sites_that_cache_under_th
     assert run.stderr.count("compiles without a cache") == 1, run.stderr
 
 
+windows_path_sep_bug = "Numba 0.68's ZIP cache locator uses Windows path separators for ZIP members"
+
+
 def test_a_zip_import_is_cached_by_numba_from_0_61(tmp_path):
     # The warning sends an archive's user to a .zip, which numba caches from
     # 0.61 on, in the user's cache directory whatever NUMBA_CACHE_DIR says.
@@ -142,6 +145,8 @@ def test_a_zip_import_is_cached_by_numba_from_0_61(tmp_path):
                NUMBA_CACHE_DIR=str(tmp_path / "cache"))
     env.pop("NUMBOX_JIT_OPTIONS", None)
     run = _run(env, tmp_path)
+    if windows_path_sep_bug in run.stderr:
+        pytest.skip(windows_path_sep_bug)
     assert run.returncode == 0 and str(archive) in run.stdout, run.stderr
     cached = tuple(int(part) for part in numba.__version__.split(".")[:2]) >= (0, 61)
     assert ("compiles without a cache" not in run.stderr) == cached, run.stderr
@@ -297,6 +302,8 @@ def test_a_pyc_in_a_zip_asks_by_the_file_it_was_compiled_from(tmp_path, tree):
     env.pop("NUMBOX_JIT_OPTIONS", None)
     run = subprocess.run([sys.executable, "-W", "always", "-c", IMPORT_LIBM], capture_output=True, text=True,
                          env=env, cwd=str(tmp_path))
+    if windows_path_sep_bug in run.stderr:
+        pytest.skip(windows_path_sep_bug)
     assert run.returncode == 0 and str(archive) in run.stdout, run.stderr
     assert run.stderr.count("compiles without a cache") == 1, run.stderr
     assert "source is not a file on disk" in run.stderr and "holding its source files" in run.stderr, run.stderr
@@ -331,6 +338,8 @@ def test_a_stale_pyc_beside_its_source_in_a_zip_is_passed_over_as_zipimport_pass
     env.pop("NUMBOX_JIT_OPTIONS", None)
     run = subprocess.run([sys.executable, "-W", "always", "-c", IMPORT_LIBM], capture_output=True, text=True,
                          env=env, cwd=str(tmp_path))
+    if windows_path_sep_bug in run.stderr:
+        pytest.skip(windows_path_sep_bug)
     assert run.returncode == 0 and run.stdout.strip().endswith("libm.py"), run.stderr
     if _zip_is_cached():
         assert "compiles without a cache" not in run.stderr, run.stderr
@@ -357,6 +366,8 @@ def test_a_stale_pyc_whose_source_in_the_zip_does_not_compile_is_passed_over(tmp
                NUMBA_CACHE_DIR=str(tmp_path / "cache"))
     env.pop("NUMBOX_JIT_OPTIONS", None)
     run = _run(env, tmp_path)
+    if windows_path_sep_bug in run.stderr:
+        pytest.skip(windows_path_sep_bug)
     assert run.returncode == 0 and str(archive) in run.stdout, run.stderr
     if _zip_is_cached():
         assert "compiles without a cache" not in run.stderr, run.stderr
@@ -382,6 +393,8 @@ def test_a_stray_pyc_in_a_zip_that_nothing_imports_is_passed_over(tmp_path, dama
                NUMBA_CACHE_DIR=str(tmp_path / "cache"))
     env.pop("NUMBOX_JIT_OPTIONS", None)
     run = _run(env, tmp_path)
+    if windows_path_sep_bug in run.stderr:
+        pytest.skip(windows_path_sep_bug)
     assert run.returncode == 0 and str(archive) in run.stdout, run.stderr
     if _zip_is_cached():
         assert "compiles without a cache" not in run.stderr, run.stderr
@@ -480,6 +493,8 @@ def test_a_moved_zip_whose_pyc_members_name_its_old_path_compiles_uncached_and_i
     env.pop("NUMBOX_JIT_OPTIONS", None)
     run = subprocess.run([sys.executable, "-W", "always", "-c", IMPORT_LIBM], capture_output=True, text=True,
                          env=env, cwd=str(tmp_path))
+    if windows_path_sep_bug in run.stderr:
+        pytest.skip(windows_path_sep_bug)
     assert run.returncode == 0 and str(moved) in run.stdout, run.stderr
     assert run.stderr.count("compiles without a cache") == 1, run.stderr
     if _zip_is_cached():
@@ -557,6 +572,10 @@ def test_a_zip_import_whose_location_for_one_directory_stopped_being_writable_ta
     env.pop("NUMBOX_JIT_OPTIONS", None)
     warm = _run(env, tmp_path)
     assert warm.returncode == 0, warm.stderr
+    if "use a path without a .zip-named directory" in warm.stderr:
+        pytest.skip("numba's caching doesn't distinguish directory with .zip in its name from an archive from 0.68 on")
+    if "put all source .py file(s) in .zip" in warm.stderr:
+        pytest.skip("numba's caching demands .py sources in a .zip from 0.68 on")
     if not _zip_is_cached():
         pytest.skip("numba caches a .zip from 0.61 on")
     # Under XDG_CACHE_HOME on Linux, under Library/Caches on macOS.
diff --git a/test/core/test_proxy.py b/test/core/test_proxy.py
index 0bb0723d..f0c27813 100644
--- a/test/core/test_proxy.py
+++ b/test/core/test_proxy.py
@@ -18,6 +18,7 @@
 from numbox.core.bindings.errno import errno_get
 from numbox.core.bindings.libc import getenv, memcpy
 from numbox.core.bindings.call import _call_lib_func
+from numbox.core.configurations import numba_version
 from numbox.core.proxy.proxy import proxy, proxy_if_available, make_proxy_name
 from numbox.utils.derive_wap import DeriveFunctionType, DeriveWAP, jit_addr_supported
 from numbox.utils.lowlevel import array_data_p, get_unicode_data_p
@@ -602,10 +603,11 @@ def call_through_declared_plain(f, x):
 
 
 @pytest.mark.skipif(not jit_addr_supported(), reason=_JIT_ADDR_REASON)
-def test_proxy_as_func_mixed_with_a_numba_native_wrapper_fails_to_unify():
-    """Characterization of a narrowing: a heterogeneous tuple of function values is refused.
+def test_proxy_as_func_mixed_with_a_numba_native_wrapper_fails_to_unify_for_numba_lt_68_and_works_for_numba_gte_68():
+    """Characterization of a narrowing: a heterogeneous tuple of function values is refused
+    for numba<0.68.
 
-    numba unifies a tuple's element types in ``unified_function_type`` with a bare
+    numba<0.68.0 unifies a tuple's element types in ``unified_function_type`` with a bare
     class-identity comparison, which runs before any of numbox's conversions get a say, so a
     ``DeriveFunctionType`` element beside a plain ``FunctionType`` one trips a message-less
     ``AssertionError`` out of ``numba/core/utils.py``. The same tuple returned a value while
@@ -615,7 +617,7 @@ def test_proxy_as_func_mixed_with_a_numba_native_wrapper_fails_to_unify():
     Why the two types cannot simply be made to compare equal is worked through in
     ``test/utils/test_derive_wap.py::test_the_derive_type_stays_distinct_from_the_plain_function_type``.
 
-    numba's assert carries no message, so the frame it was raised from is checked instead of any
+    numba<0.68.0's assert carries no message, so the frame it was raised from is checked instead of any
     text. Matching on ``AssertionError`` alone would be satisfied by an unrelated one raised
     anywhere in the same call.
     """
@@ -629,11 +631,14 @@ def native(x):
     def use_pair(pair, x):
         return pair[0](x) + pair[1](x)
 
-    with pytest.raises(AssertionError) as raised:
-        use_pair((aux_raises.as_func, foreign), -3.0)
-    assert raised.traceback[-1].name == "unified_function_type", (
-        f"the refusal moved out of numba's function-type unification: {raised.traceback[-1].name}"
-    )
+    if numba_version >= 68:
+        assert use_pair((aux_raises.as_func, foreign), -3.0) == 5
+    else:
+        with pytest.raises(AssertionError) as raised:
+            use_pair((aux_raises.as_func, foreign), -3.0)
+        assert raised.traceback[-1].name == "unified_function_type", (
+            f"the refusal moved out of numba's function-type unification: {raised.traceback[-1].name}"
+        )
 
 
 if __name__ == "__main__":