zarr-developers · dstansby · Jun 18, 2025
diff --git a/changes/2774.feature.rst b/changes/2774.feature.rst
diff --git a/changes/2921.bugfix.rst b/changes/2921.bugfix.rst
diff --git a/changes/3021.feature.rst b/changes/3021.feature.rst
diff --git a/changes/3066.feature.rst b/changes/3066.feature.rst
diff --git a/changes/3068.bugfix.rst b/changes/3068.bugfix.rst
diff --git a/changes/3081.feature.rst b/changes/3081.feature.rst
diff --git a/changes/3082.feature.rst b/changes/3082.feature.rst
diff --git a/changes/3100.bugfix.rst b/changes/3100.bugfix.rst
diff --git a/changes/3103.bugfix.rst b/changes/3103.bugfix.rst
diff --git a/changes/3127.bugfix.rst b/changes/3127.bugfix.rst
diff --git a/changes/3128.bugfix.rst b/changes/3128.bugfix.rst
diff --git a/changes/3130.feature.rst b/changes/3130.feature.rst
diff --git a/docs/release-notes.rst b/docs/release-notes.rst
@@ -3,6 +3,40 @@ Release notes
 
 .. towncrier release notes start
 
+3.0.9 (2025-06-18)
+------------------
+
+Features
+~~~~~~~~
+
+- Add `zarr.storage.FsspecStore.from_mapper()` so that `zarr.open()` supports stores of type `fsspec.mapping.FSMap`. (:issue:`2774`)
+- Implemented ``move`` for ``LocalStore`` and ``ZipStore``. This allows users to move the store to a different root path. (:issue:`3021`)
+- Added `~zarr.errors.GroupNotFoundError`, which is raised when attempting to open a group that does not exist. (:issue:`3066`)
+- Adds ``fill_value`` to the list of attributes displayed in the output of the ``AsyncArray.info()`` method. (:issue:`3081`)
+- Use :py:func:`numpy.zeros` instead of :py:func:`np.full` for a performance speedup when creating a `zarr.core.buffer.NDBuffer` with `fill_value=0`. (:issue:`3082`)
+- Port more stateful testing actions from `Icechunk <https://icechunk.io>`_. (:issue:`3130`)
+
+
+Bugfixes
+~~~~~~~~
+
+- Ignore stale child metadata when reconsolidating metadata. (:issue:`2921`)
+- Trying to open an array with ``mode='r'`` when the store is not read-only now raises an error. (:issue:`3068`)
+- For Zarr format 2, allow fixed-length string arrays to be created without automatically inserting a
+  ``Vlen-UT8`` codec in the array of filters. Fixed-length string arrays do not need this codec. This
+  change fixes a regression where fixed-length string arrays created with Zarr Python 3 could not be read with Zarr Python 2.18. (:issue:`3100`)
+- When creating arrays without explicitly specifying a chunk size using `zarr.create` and other
+  array creation routines, the chunk size will now set automatically instead of defaulting to the data shape.
+  For large arrays this will result in smaller default chunk sizes.
+  To retain previous behaviour, explicitly set the chunk shape to the data shape.
+
+  This fix matches the existing chunking behaviour of
+  `zarr.save_array` and `zarr.api.asynchronous.AsyncArray.create`. (:issue:`3103`)
+- When `zarr.save` has an argument `path=some/path/` and multiple arrays in `args`, the path resulted in `some/path/some/path` due to using the `path`
+  argument twice while building the array path. This is now fixed. (:issue:`3127`)
+- Fix `zarr.open` default for argument `mode` when `store` is `read_only` (:issue:`3128`)
+
+
 3.0.8 (2025-05-19)
 ------------------