Made for military purpose but later used for civilian purpose

I would recommend to first contact the authorities to confirm that your new product is indeed considered to have been modified for military purposes. It depends on the extent of modifications and for some goods that were subject to insignificant changes, export license may not be required at all. If it is indeed the case, however, and your product really falls under military goods classifications, then yes, you will need to request an export license – even if it is also used for civilian purposes in line with dual-use regulations. And by the way – also civilian goods with military end-use purpose would require a license.