Need to know which MIMO config KPN Box 12 and 14 supports 3x3? 4x4 ?

Hi @pioneerkartik! That's a good question.

I haven't been able to find the answer, so I'll link you to the Box 12 specifications and the Box 14 specifications. 
Hopefully your answer can be found there!

If the pages are difficult to read in Dutch, know you can translate them through Google Translate. 
If you put the weblink in there and translate it, another link will show up in the box with your preferred language. If you click the link there, you'll see the page in your preferred language!