--- title: "pymongo Breaking Changes on PyPI | Since.dev" description: "What each pymongo release removed, renamed or changed: 427 breaking changes in 7 versions on PyPI, each with its source." canonical_url: https://since.dev/packages/pypi/pymongo last_updated: 2026-09-03 --- # pymongo breaking changes Every breaking API change we have recorded in pymongo on PyPI: 427 breaking changes in 7 versions. Below are its newest 6 versions, removals and renames first, each with its source. Newest change September 3, 2026 ## 4.18.0 178 breaking changes, first published September 3, 2026. - **Removed** `pymongo.asynchronous.aggregation.Server.checkout` Server.checkout was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.aggregation.Server.operation_to_command` Server.operation_to_command was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.aggregation.Server.run_operation` Server.run_operation was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.bulk.NotPrimaryError` pymongo.asynchronous.bulk.NotPrimaryError was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.change_stream.AsyncConnection` pymongo.asynchronous.change_stream.AsyncConnection was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.client_session.Binary` pymongo.asynchronous.client_session.Binary was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.client_session.ExecutionTimeout` pymongo.asynchronous.client_session.ExecutionTimeout was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.client_session.NetworkTimeout` pymongo.asynchronous.client_session.NetworkTimeout was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.encryption.BSONError` pymongo.asynchronous.encryption.BSONError was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) - **Removed** `pymongo.asynchronous.encryption.BulkWriteResult` pymongo.asynchronous.encryption.BulkWriteResult was removed in pymongo 4.18.0 [pypi.org](https://pypi.org/project/pymongo/4.18.0/) And 168 more in this version. ## 4.17.0 40 breaking changes, first published April 20, 2026. - **Removed** `pymongo.common.validate_auth_option` pymongo.common.validate_auth_option was removed in pymongo 4.17.0 [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Removed** `pymongo.common.validate_int_or_basestring` pymongo.common.validate_int_or_basestring was removed in pymongo 4.17.0 [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Removed** `pymongo.common.validate_positive_integer_or_none` pymongo.common.validate_positive_integer_or_none was removed in pymongo 4.17.0 [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Renamed** `pymongo.asynchronous.cursor.AsyncConnection` Use pymongo.asynchronous.cursor_base.AsyncConnection instead. [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Renamed** `pymongo.synchronous.cursor.Connection` Use pymongo.synchronous.cursor_base.Connection instead. [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Behavior changed** Index information returned by the driver now includes simple collation. Code that compares or parses index information may see an extra field. [github.com](https://github.com/mongodb/mongo-python-driver/releases/tag/4.17.0) - **Behavior changed** On replica sets, server selection now deprioritizes a server only after overload errors, not for other errors. Code that relied on the previous deprioritization may see different server choices. [github.com](https://github.com/mongodb/mongo-python-driver/releases/tag/4.17.0) - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCommandCursor` Was class AsyncCommandCursor(Generic\[\_DocumentType\]); now class AsyncCommandCursor(\_AsyncCursorBase\[\_DocumentType\]). [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCommandCursor.cursor_id` Was cursor_id: int; now cursor_id: Optional\[int\]. [pypi.org](https://pypi.org/project/pymongo/4.17.0/) - **Signature changed** `pymongo.asynchronous.change_stream.AsyncCommandCursor` Was class AsyncCommandCursor(Generic\[\_DocumentType\]); now class AsyncCommandCursor(\_AsyncCursorBase\[\_DocumentType\]). [pypi.org](https://pypi.org/project/pymongo/4.17.0/) And 30 more in this version. ## 4.16.0 16 breaking changes, first published January 7, 2026. - **Signature changed** `bson.Binary.as_vector` Was def as_vector(self) -> BinaryVector; now def as_vector(self, return_numpy: bool = False) -> BinaryVector. [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `bson.binary.BinaryVector.__init__` Was def \_\_init\_\_(self, data: Sequence\[float | int\], dtype: BinaryVectorDtype, padding: int = 0); now def \_\_init\_\_(self, data: Union\[Sequence\[float | int\], npt.NDArray\[np.number\]\], dtype: BinaryVectorDtype, padding: int = 0). [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `bson.Binary.from_vector` Was @classmethod def from_vector(cls: Type\[Binary\], vector: Union\[BinaryVector, list\[int\], list\[float\]\], dtype: Optional\[BinaryVectorDtype\] = None, padding: Optional\[int\] = None) -> Binary; now @classmethod def from_vector(cls... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCollection.find_one_and_delete` Was async def find_one_and_delete(self, filter: Mapping\[str, Any\], projection: Optional\[Union\[Mapping\[str, Any\], Iterable\[str\]\]\] = None, sort: Optional\[\_IndexList\] = None, hint: Optional\[\_IndexKeyHint\] = None, session... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCollection.find_one_and_replace` Was async def find_one_and_replace(self, filter: Mapping\[str, Any\], replacement: Mapping\[str, Any\], projection: Optional\[Union\[Mapping\[str, Any\], Iterable\[str\]\]\] = None, sort: Optional\[\_IndexList\] = None, upsert: bool = False... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCollection.find_one_and_update` Was async def find_one_and_update(self, filter: Mapping\[str, Any\], update: Union\[Mapping\[str, Any\], \_Pipeline\], projection: Optional\[Union\[Mapping\[str, Any\], Iterable\[str\]\]\] = None, sort: Optional\[\_IndexList\] = None, upsert: bool = False... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCommandCursor.__init__` Was def \_\_init\_\_(self, collection: AsyncCollection\[\_DocumentType\], cursor_info: Mapping\[str, Any\], address: Optional\[\_Address\], batch_size: int = 0, max_await_time_ms: Optional\[int\] = None, session: Optional\[AsyncClientSession\] = None... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.asynchronous.collection.AsyncRawBatchCommandCursor.__init__` Was def \_\_init\_\_(self, collection: AsyncCollection\[\_DocumentType\], cursor_info: Mapping\[str, Any\], address: Optional\[\_Address\], batch_size: int = 0, max_await_time_ms: Optional\[int\] = None, session: Optional\[AsyncClientSession\] = None... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.asynchronous.mongo_client.Topology.select_servers` Was async def select_servers(self, selector: Callable\[\[Selection\], Selection\], operation: str, server_selection_timeout: Optional\[float\] = None, address: Optional\[\_Address\] = None, operation_id: Optional\[int\] = None) -> list\[Server\]; now... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) - **Signature changed** `pymongo.collection.Collection.find_one_and_delete` Was def find_one_and_delete(self, filter: Mapping\[str, Any\], projection: Optional\[Union\[Mapping\[str, Any\], Iterable\[str\]\]\] = None, sort: Optional\[\_IndexList\] = None, hint: Optional\[\_IndexKeyHint\] = None, session: Optional\[ClientSession\] =... [pypi.org](https://pypi.org/project/pymongo/4.16.0/) And 6 more in this version. ## 4.15.4 1 breaking change, first published November 11, 2025. - **Signature changed** `pymongo.asynchronous.aggregation.AsyncClientSession.with_transaction` Was async def with_transaction(self, callback: Callable\[\[AsyncClientSession\], Coroutine\[Any, Any, \_T\]\], read_concern: Optional\[ReadConcern\] = None, write_concern: Optional\[WriteConcern\] = None, read_preference: Optional\[\_ServerMode\] =... [pypi.org](https://pypi.org/project/pymongo/4.15.4/) ## 4.15.3 4 breaking changes, first published October 7, 2025. - **Signature changed** `pymongo.asynchronous.aggregation.AsyncCollection.distinct` Was async def distinct(self, key: str, filter: Optional\[Mapping\[str, Any\]\] = None, session: Optional\[AsyncClientSession\] = None, comment: Optional\[Any\] = None, hint: Optional\[\_IndexKeyHint\] = None, \*\*kwargs: Any) -> list\[str\]; now async... [pypi.org](https://pypi.org/project/pymongo/4.15.3/) - **Signature changed** `pymongo.asynchronous.collection.AsyncCursor.distinct` Was async def distinct(self, key: str) -> list\[str\]; now async def distinct(self, key: str) -> list\[Any\]. [pypi.org](https://pypi.org/project/pymongo/4.15.3/) - **Signature changed** `pymongo.collection.Collection.distinct` Was def distinct(self, key: str, filter: Optional\[Mapping\[str, Any\]\] = None, session: Optional\[ClientSession\] = None, comment: Optional\[Any\] = None, hint: Optional\[\_IndexKeyHint\] = None, \*\*kwargs: Any) -> list\[str\]; now def distinct(self... [pypi.org](https://pypi.org/project/pymongo/4.15.3/) - **Signature changed** `pymongo.cursor.Cursor.distinct` Was def distinct(self, key: str) -> list\[str\]; now def distinct(self, key: str) -> list\[Any\]. [pypi.org](https://pypi.org/project/pymongo/4.15.3/) ## 4.15.1 74 breaking changes, first published September 16, 2025. - **Removed** `pymongo.asynchronous.encryption.async_receive_kms` pymongo.asynchronous.encryption.async_receive_kms was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.asynchronous.encryption.async_sendall` pymongo.asynchronous.encryption.async_sendall was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.asynchronous.encryption.AsyncBaseConnection` pymongo.asynchronous.encryption.AsyncBaseConnection was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.asynchronous.encryption.PyMongoKMSProtocol` pymongo.asynchronous.encryption.PyMongoKMSProtocol was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.asynchronous.pool.AsyncBaseConnection` pymongo.asynchronous.pool.AsyncBaseConnection was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.network_layer.async_receive_kms` pymongo.network_layer.async_receive_kms was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.network_layer.AsyncBaseConnection` pymongo.network_layer.AsyncBaseConnection was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.network_layer.BaseConnection` pymongo.network_layer.BaseConnection was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.network_layer.PyMongoBaseProtocol` pymongo.network_layer.PyMongoBaseProtocol was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) - **Removed** `pymongo.network_layer.PyMongoKMSProtocol` pymongo.network_layer.PyMongoKMSProtocol was removed in pymongo 4.15.1 [pypi.org](https://pypi.org/project/pymongo/4.15.1/) And 64 more in this version. ## Check your code These are the changes. To see which of them reach your code, [scan a public repository](https://since.dev/scan.md), or have your coding agent call `check_code` with your manifest or lockfile over [MCP](https://since.dev/docs.md#mcp). [The API](https://since.dev/docs.md#api) reads every change in every version, not only the newest. On Team and up, a fix pull request opens for the changes that reach a connected repository. Nothing merges or deploys. ## Put your code on continuous management. Scan a public repository now, or give your agent one line. ### See how out of date your code is. [Scan a repository](https://since.dev/scan.md). Any public GitHub repository. No sign-in. ### Tell your agent what changed since it was trained. `claude mcp add --transport http since https://api.since.dev/mcp` --- Every page on this site as Markdown: https://since.dev/sitemap.md. For agents: https://since.dev/llms.txt.