gistfile1.txt

Module developer creates a module
They wish to create a single module but have enhanced API functionality for 2.1+ because they depend on some API features only available on that platform.  The API they are using also may have changed between platform versions (think Android contacts).

For users of the 1.6 module - they will have reduced functionality but broader reach.

Option (1)
They release 2 differently named modules and the module consumer has to download/buy both

Option (2)
Use a folder structure for modules that differentiate based on platform.
It's up to the module consumer to pick one and for the target platform to trickle up the build tree.  ie if they want 2.1 func - then their target userbase are 2.1+ users

\super-sexy-alerts
  \0.1
    \target-1.6
      meta-data.xml
      myPackage.jar
    \target-2.1
     meta-data.xml
     myPackage.jar