How to create a new product reader - XMLProductDirectory missing - snap version 6

I’m trying to build product reader plugin
I tried to build using maven
org.esa.s1tbx version 7.0.0-SNAPSHOT
Which give unsuported plugin for SNAP application version 6 [your life version on production latest http://step.esa.int/main/download/ ]as its minmium require version 7
I tried to reduce org.esa.s1tbx to version 6.0.0
But I can’t find “org.esa.s1tbx.commons.io.XMLProductDirectory” even the whole package org.esa.s1tbx.commons.io
Should I copy classes from org.esa.s1tbx version 7.0.0-SNAPSHOT and have my own copy?

If you want to build a plugin for version 6, then you should build from the 6.x branch of all repos.
However, I would advise building from the master branch and building everything for version 7. For this, you will need to build all of SNAP in version 7 to ensure it’s compatable.

If i build it from version 7, how to make it support SNAP application
life version on production latest http://step.esa.int/main/download/
[ The current version is 6.0.0 (15.01.2018 15:25 UTC ).]
so customers can use this plugin

Version 7 should be released in May but, if you really want to build a version 6.0 then you need to use the 6.x branch of the repos