Minimal Ansible version required

[busterswt]

When installing using Ansible 1.9.4, I observed the following error during 'vagrant up':

...
==> controller-01: Exporting NFS shared folders...
==> controller-01: Preparing to edit /etc/exports. Administrator privileges will be required...
==> controller-01: Mounting NFS shared folders...
==> controller-01: Updating /etc/hosts file on active guest machines...
==> controller-01: Updating /etc/hosts file on host machine (password may be required)...
==> controller-01: Running provisioner: shell...
controller-01: Running: /var/folders/qj/q9frl5y129x6cbvdscfr_vt00000gn/T/vagrant-shell20171010-25396-2woo5v.sh
==> controller-01: /tmp/vagrant-shell: line 3: /root/.ssh/known_hosts: No such file or directory
==> controller-01: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCwqecjzCGZIBq5QH8oDSxR2A8EnnX3SlPWRtcFsYEUI3iV2p6BvwIgOkIecZN5a8e3ba0+C5IYrfPavXmao0R0bNJzim6U+N0ZKtU4GvBV23lIBg9KXrptwU9u2eJJRf4bIGIxLx45CQ57ucpWnNETlps25N/lb4LMdEX1mpOQWloZ5DlriWi+nOHm1QuenOKzjVI49YClRQX4B2JHB/vVCMgzyszOA/VO9DUNp4/Zr7WLxrxbUjgc2fdL5cw9Xv10KmaLL12wZ//ZutGqGRjrPWyG8thjSy5ZBgy4FOxGgx3+mlm1zmVSA+jVQ7OPeYoCMjad8mI02nqYer2+4KBH root@compute-01
==> controller-01: Running provisioner: shell...
controller-01: Running: /var/folders/qj/q9frl5y129x6cbvdscfr_vt00000gn/T/vagrant-shell20171010-25396-t2iaw9.sh
==> controller-01: mesg: ttyname failed: Inappropriate ioctl for device
==> controller-01: Running provisioner: ansible...
controller-01: Running ansible-playbook...
ERROR: rescue is not a legal parameter in an Ansible task or handler
Ansible failed to complete successfully. Any error output should be
visible above. Please fix these errors and try again.
...

Upgrading my local Ansible version to 2.4 has resolved that issue.