## Driver Migration Guide
Please read our [Driver Migration Guide](https://neo4j.com/docs/migration-guide/4.0/upgrade-driver/) for guidance and breaking changes when migrating from 1.7 drivers to 4.X drivers.

## Changelog
### 4.3.9
* Fix pool closing stale connections that are in use ([#632](https://github.com/neo4j/neo4j-python-driver/pull/632)). Especially, but not only, in concurrent contexts, this would lead to all sorts of unspecific errors.

### 4.3.8
* Fix wrong serialization of the `Time` type's timezone ([#617](https://github.com/neo4j/neo4j-python-driver/pull/617)).

### 4.3.7
* Use `selectors.DefaultSelector` instead of `select.select` which resolves the number of simultaneously open files (including sockets) being limited to 1024 on all operating systems that support it ([#605](https://github.com/neo4j/neo4j-python-driver/pull/605)).
* Log the reason when a secure connection could not be established ([#609](https://github.com/neo4j/neo4j-python-driver/pull/609)).

### 4.3.6
* Fix bug where the driver would try to remove the same connection from the pool multiple times causing `ValueError: deque.remove(x): x not in deque` ([#598](https://github.com/neo4j/neo4j-python-driver/pull/598)).
* Improve logging around connection errors ([#595](https://github.com/neo4j/neo4j-python-driver/pull/595)).

### 4.3.5
* Improve compatibility of driver's datetime implementation with Windows ([#588](https://github.com/neo4j/neo4j-python-driver/pull/588)).
* Fix potential endless loop on calling `Result.peek()` when `fetch_size=0` is configured ([#590](https://github.com/neo4j/neo4j-python-driver/pull/590))

### 4.3.4
* Add support for `connection.recv_timeout_seconds` connection hint ([#557](https://github.com/neo4j/neo4j-python-driver/pull/557), [#570](https://github.com/neo4j/neo4j-python-driver/pull/570)).

### 4.3.3
* Bug fix ([#561](https://github.com/neo4j/neo4j-python-driver/pull/561)): when handling multiple query-results in a single transaction, the driver could sent too many `PULL` messages to the server causing it to respond with `DatabaseError: Unknown statement ID…`. 

### 4.3.2
* Bug fix that will enable using multi database functionality with 4.0.x-enterprise servers ([#559](https://github.com/neo4j/neo4j-python-driver/pull/559)).  
  **Note**: only server versions 4.3.x and 4.2.x are fully supported and tested with this driver version. Other functionality might not work and won't get patched.

### 4.3.1
* Minor bug fix ([#546](https://github.com/neo4j/neo4j-python-driver/pull/546)): properly close connections when removed from the connection pool due to being stale (e.g., after authorization expiration).

### 4.3.0
* no changes

### 4.3.0rc1
* no changes

### 4.3.0b1
* Optimization: Refresh connection pool on Neo.ClientError.Security.AuthorizationExpired, (e.g. expired LDAP token). [#540](https://github.com/neo4j/neo4j-python-driver/pull/540)
* Bug fix: clean up connections released back into the connection pool. [#539](https://github.com/neo4j/neo4j-python-driver/pull/539)

### 4.3.0a1

* Connectivity improvements [#533](https://github.com/neo4j/neo4j-python-driver/pull/533), [#531](https://github.com/neo4j/neo4j-python-driver/pull/531), [#530](https://github.com/neo4j/neo4j-python-driver/pull/530), [#518](https://github.com/neo4j/neo4j-python-driver/pull/518), [#517](https://github.com/neo4j/neo4j-python-driver/pull/517)
* Fixed bugs around surfacing connectivity errors. [#519](https://github.com/neo4j/neo4j-python-driver/pull/519), [#517](https://github.com/neo4j/neo4j-python-driver/pull/517)
* Fixed spatial types when passed non-float arguments.
* Implemented bolt 4.3 protocol.