JPK in the Dynamics NAV system is already available from July 2016 – for all companies… large sized, medium and small…
You probably already know it:
Implementation of Uniform Control File is related to earlier adoption of art. 193a of general tax law – imposing an obligatory introduction of Uniform Control File, introducted by act from 10 September 2015 about the change of act – General tax law and other acts (Dz. U. z 2015 r. poz. 1649) and shall enter into force on 1 July 2016.
Therefore from 1 July 2016 Uniform Control File is available in Dynamics NAV systems for free! (within the Polish location)