Why do you need contacts on the upper housing module XBee Pro S2B ZigBee 2.4 GHz?

Why do you need contacts on the upper housing module XBee S2B ZigBee 2.4 GHz?

What do you mean by upper level contacts? From the sounds of it, you are referring to the Programming header used by Digi on their test fixture to write code to and write the Calibration settings with.

https://www.digi.com/products/xbee-rf-solutions/embedded-rf-modules-modems/xbee-zigbee/product-images/xbee-s2c-zigbee

On this image in the right side of module there is 10 pins. On S2B version there are 20 pins.

I can`t use this pins?

No, you can use All of the pins on the through hole version and Pads on the surface mount version that are available.

They have different amounts of pins for a reason. The through hole version is there to hold comparability with existing hardware and a footprint that has been around for more than 10 years. The second or Surface mount version is a New product. Since the Surface mount version added the use of a SPI port, it could be added in a different location on the pins without breaking the standard UART, VCC and GND pins.

I dont found haw I can use these pins? In datasheet there isnt information about it (actually, I don`t see the datasheet on your site)

Try going to https://www.digi.com/support/productdetail?pid=4838&type=documentation