We only maintain the lastest version of Simple DNS Plus.
Whenever we release a new version (major/minor) of Simple DNS Plus, older versions are no longer supported.
With any license purchase (new or upgrade), you receive one year of free upgrade protection.
This entitles you to receive any new version of the software for free, regardless of major or minor update, within one year of the purchase.
If you want to stay up to date after the free upgrade protection period, you will need to purchase an upgrade when a new version (major/minor) is released. This purchase then resets the free upgrade protection period.