The Main Release of DataMiner is the version that has one major upgrade per year. On a regular basis, Cumulative Updates (CU) become available for this main version. These updates contain all the latest fixes up to that point in time, so you only need to install the latest CU in order to have all the improvements. In general, no new features are added to this version, except for specific isolated cases that do not affect existing functionality.
In the Main Release folder, you can find the latest upgrade package for a full upgrade to this version, and also the latest Cumulative Update if you already have this version and you just want to install the latest updates. It is recommended to use the Main Release for a production environment that does not require specific new features only available in the Feature Release. It is also advised to install the Cumulative Updates on a regular basis.
The Feature Release of DataMiner is the track of the DataMiner software introducing new features on a regular basis. This version of DataMiner is fully supported in a production environment, but typically only used when a specific feature of this version is needed. This version track has time-limited support for cumulative updates, as it is required to follow the track of the consecutive upgrades in order to get all the improvements. In other words, following this fast track implies following those upgrades in order to have an updated system.