tornado==4.5
# Task queues
celery>=3.1.24,<4.0.0
# Messaging library (AMQP)
kombu>=3.0.36,<3.1
# Promises (celery dependency)
vine==1.1.3
# Caching utilities
cachetools==2.0.0

tornado==4.5
# Task queues
celery>=3.1.24,<=4.0.2
# Messaging library (AMQP)
kombu>=3.0.36,<=4.0.2
# Promises (celery dependency)
vine==1.1.3
# Caching utilities
cachetools==2.0.0

Add support for celery v4
Add support for celery v4
