=================
- BREAKING CHANGE: Improved the performance of :meth:`~mongoengine.Document.save()`
by removing the call to :meth:`~mongoengine.Document.ensure_indexes` unless
``meta['auto_create_index_on_save']`` is set to True. With the default settings, Document indexes
will still be created on the fly, during the first usage of the collection (query, insert, etc),
they will just not be re-created whenever .save() is called.
- Added meta ``auto_create_index_on_save`` so you can enable index creation
on :meth:`~mongoengine.Document.save()` (as it was < 0.26.0).
- BREAKING CHANGE: remove deprecated method ``ensure_index`` (replaced by ``create_index`` long time ago).
- Addition of Decimal128Field: :class:`~mongoengine.fields.Decimal128Field` for accurate representation of Decimals (much better than the legacy field DecimalField).
Although it could work to switch an existing DecimalField to Decimal128Field without applying a migration script,
it is not recommended to do so (DecimalField uses float/str to store the value, Decimal128Field uses Decimal128).
- BREAKING CHANGE: When using ListField(EnumField) or DictField(EnumField), the values weren't always cast into the Enum (2531)
- BREAKING CHANGE (bugfix) Querying ObjectIdField or ComplexDateTimeField with None no longer raise a ValidationError (2681)
- Allow updating a field that has an operator name e.g. "type" with .update(set__type="foo"). It was raising an error previously. 2595