Our general policy is to support an earlier version for a period of two years, after which customers must have migrated to the latest available version. Support includes both backward compatibility with earlier products (if technically possible), as well as providing updates and hotfixes for outgoing versions. If a solution to a particular issue is available in a later version, customers are encouraged to upgrade their environments. Customers with specific needs regarding support for earlier versions are invited to contact us.

Please consult the following article for more details:

Supported branch versions and product lifecycle
https://kb.nomachine.com/AR06P00985