Mongoengine

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- Fix for reloading of strict with special fields. 1156

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- ``SaveConditionError`` is now importable from the top level package. 1165
- Add a ``QuerySet.upsert_one`` method. 1157

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- Fix ``read_preference`` (it had chaining issues with PyMongo v2.x and it didn't work at all with PyMongo v3.x). 1042

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- Allow shard key to point to a field in an embedded document. 551
- Allow arbirary metadata in fields. 1129
- ReferenceFields now support abstract document types. 837

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- Fix infinite recursion with cascade delete rules under specific conditions. 1046
- Fix ``CachedReferenceField`` bug when loading cached docs as ``DBRef`` but failing to save them. 1047
- Fix ignored chained options. 842
- ``Document.save``'s ``save_condition`` error raises a ``SaveConditionError`` exception. 1070
- Fix ``Document.reload`` for the ``DynamicDocument``. 1050
- ``StrictDict`` & ``SemiStrictDict`` are shadowed at init time. 1105
- Fix ``ListField`` negative index assignment not working. 1119
- Remove code that marks a field as changed when the field has a default value but does not exist in the database. 1126
- Remove test dependencies (nose and rednose) from install dependencies. 1079
- Recursively build a query when using the ``elemMatch`` operator. 1130
- Fix instance back references for lists of embedded documents. 1131

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- Django support was removed and will be available as a separate extension. 958
- Allow to load undeclared field with meta attribute 'strict': False 957
- Support for PyMongo 3+ 946
- Removed get_or_create() deprecated since 0.8.0. 300
- Improve Document._created status when switch collection and db 1020
- Queryset update doesn't go through field validation 453
- Added support for specifying authentication source as option ``authSource`` in URI. 967
- Fixed mark_as_changed to handle higher/lower level fields changed. 927
- ListField of embedded docs doesn't set the _instance attribute when iterating over it 914
- Support += and *= for ListField 595
- Use sets for populating dbrefs to dereference
- Fixed unpickled documents replacing the global field's list. 888
- Fixed storage of microseconds in ComplexDateTimeField and unused separator option. 910
- Don't send a "cls" option to ensureIndex (related to https://jira.mongodb.org/browse/SERVER-769)
- Fix for updating sorting in SortedListField. 978
- Added __ support to escape field name in fields lookup keywords that match operators names 949
- Fix for issue where FileField deletion did not free space in GridFS.
- No_dereference() not respected on embedded docs containing reference. 517
- Document save raise an exception if save_condition fails 1005
- Fixes some internal _id handling issue. 961
- Updated URL and Email Field regex validators, added schemes argument to URLField validation. 652
- Capped collection multiple of 256. 1011
- Added ``BaseQuerySet.aggregate_sum`` and ``BaseQuerySet.aggregate_average`` methods.
- Fix for delete with write_concern {'w': 0}. 1008
- Allow dynamic lookup for more than two parts. 882
- Added support for min_distance on geo queries. 831
- Allow to add custom metadata to fields 705