Backwards incompatibility - executor does not ignore unknown (new) fields in task definition

Traceback (most recent call last):
  File "/root/.pex/install/twitter.common.exceptions-0.3.3-py2-none-any.whl.14f404225d875c1e10b9b1d1a8ff8e541e8db577/twitter.common.exceptions-0.3.3-py2-none-any.whl/twitter/common/exceptions/__init__.py", line 126, in _excepting_run
    self.__real_run(*args, **kw)
  File "/root/.pex/install/twitter.common.concurrent-0.3.3-py2-none-any.whl.4f2be5d96dfe1712aadbb222638f05170f84a70e/twitter.common.concurrent-0.3.3-py2-none-any.whl/twitter/common/concurrent/deferred.py", line 42, in run
    self._closure()
  File "/var/lib/mesos/slaves/20150317-173140-1831412746-5050-10511-S6285/frameworks/201104070004-0000002563-0000/executors/thermos-1428446460822-jcohen-devel-echo-0-7ad791bf-729d-4fba-bd40-306383c53e5b/runs/01851671-a7aa-48b8-a2c8-841ab9f994fe/thermos_executor/apache/aurora/executor/aurora_executor.py", line 252, in 
    defer(lambda: self._run(driver, assigned_task))
  File "/var/lib/mesos/slaves/20150317-173140-1831412746-5050-10511-S6285/frameworks/201104070004-0000002563-0000/executors/thermos-1428446460822-jcohen-devel-echo-0-7ad791bf-729d-4fba-bd40-306383c53e5b/runs/01851671-a7aa-48b8-a2c8-841ab9f994fe/thermos_executor/apache/aurora/executor/aurora_executor.py", line 90, in _run
    if not self._initialize_sandbox(driver, assigned_task):
  File "/var/lib/mesos/slaves/20150317-173140-1831412746-5050-10511-S6285/frameworks/201104070004-0000002563-0000/executors/thermos-1428446460822-jcohen-devel-echo-0-7ad791bf-729d-4fba-bd40-306383c53e5b/runs/01851671-a7aa-48b8-a2c8-841ab9f994fe/thermos_executor/apache/aurora/executor/aurora_executor.py", line 118, in _initialize_sandbox
    self._sandbox = self._sandbox_provider.from_assigned_task(assigned_task)
  File "/var/lib/mesos/slaves/20150317-173140-1831412746-5050-10511-S6285/frameworks/201104070004-0000002563-0000/executors/thermos-1428446460822-jcohen-devel-echo-0-7ad791bf-729d-4fba-bd40-306383c53e5b/runs/01851671-a7aa-48b8-a2c8-841ab9f994fe/thermos_executor/twitter/aurora/executor/bin_internal/thermos_executor_main.py", line 40, in from_assigned_task
  File "/var/lib/mesos/slaves/20150317-173140-1831412746-5050-10511-S6285/frameworks/201104070004-0000002563-0000/executors/thermos-1428446460822-jcohen-devel-echo-0-7ad791bf-729d-4fba-bd40-306383c53e5b/runs/01851671-a7aa-48b8-a2c8-841ab9f994fe/thermos_executor/apache/aurora/executor/common/task_info.py", line 71, in mesos_task_instance_from_assigned_task
    mti, refs = task_instance_from_job(MesosJob.json_loads(thermos_task), assigned_task.instanceId)
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 286, in json_loads
    else cls._filter_against_schema(json.loads(json_string)))
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 160, in __init__
    self._update_schema_data(**arg)
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 180, in _update_schema_data
    self._schema_data[attr] = self._process_schema_attribute(attr, value)
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 176, in _process_schema_attribute
    return schema_type.klazz(value)
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 160, in __init__
    self._update_schema_data(**arg)
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 180, in _update_schema_data
    self._schema_data[attr] = self._process_schema_attribute(attr, value)
  File "/root/.pex/install/pystachio-0.7.4-py2.py3-none-any.whl.54a0489cf7157f19599786595f40369fb6817043/pystachio-0.7.4-py2.py3-none-any.whl/pystachio/composite.py", line 169, in _process_schema_attribute
    raise AttributeError('Unknown schema attribute %s' % attr)
AttributeError: Unknown schema attribute endpoint