With the release and concurrent use of multiple DotNetNuke (DNN) versions among many sites, we've established a version-numbering system to try and help end users to determine which modules/version are compatible with DNN versions.

The Inventua retail DNN modules are published using a three-part version number, made up of:

dnnversion.release.patch

dnnversion: Represents the DotNetNuke version that a module was written for. 
release: Increments of the release version number represent a significant release of the module.
patch: Represents a minor or maintenance release of the module.  Patch versions are reset to zero when release version is incremented.

dnnversion	DotNetNuke Versions supported
1, 2	Supports DotNetNuke version 2.1.2.  Original versions of the Inventua retail modules were developed when there was only one version of DotNetNuke in common use, so they were labelled version 1.
3	Supports DotNetNuke version 3 (all versions - 3.0, 3.1 and 3.2) and DotNetNuke 4.  DotNetNuke 4 is backwardly-compatible with DNN 3 modules.
4	Developed for, and supports DotNetNuke version 4 only.

So a module marked "3.2.5" was written for DNN 3, is up to release version 2, and has had 5 maintenance releases since version 3.2.0.  A module marked "1.2.3" was written for DNN 2, is up to release 2 and has had 3 maintenance releases since version "1.2.0".