On 20 June 2017 NSO 4.0 and related NED versions reached the End-of-Maintenance milestone. This means that according to the Cisco EOS/EOL policy we are not planning any further maintenance releases. Any defects and issues reported from now on may require an upgrade to a later major version (currently NSO 4.4)
All customers are encouraged to plan to upgrade NSO version annually, in order to remain on an actively supported version, and to take advantage of the latest features, defect fixes, and security features.