11: With save, only use replace when an _id is specified.
6.3
===
10: MongoDBInstance now passes the subprocess output through to stderr and stdout. Callers should either capture this output separately (such as pytest already does) or set a ``.process_kwargs`` property on the instance to customize the ``stdout`` and/or ``stderr`` parameters to Popen.
6.2.1
=====
Use portend for finding available local port, eliminating remaining DeprecationWarnings.
6.2
===
Add compat module and ``compat.save`` method for supplying the ``Collection.save`` behavior, deprecated in PyMongo.
Updated PyMongo 3.0 API usage to eliminate DeprecationWarnings.
6.1.1
=====
9: Fix issue with MongoDBInstance by using ``subprocess.PIPE`` for stdout. Users may read from this pipe by reading ``instance.process.stdout``.
6.1
===
Now, suppress creation of MongoDBInstance log file in fixture and MongoDBInstance service.