But it's not yet activated they have only signalled the intent for Segwit and now they have a grace period of about 3-4 days to apply Segwit to their networks and start mining Segwit blocks. Here's my post about Segwit activation you can check it out if you like
https://steemit.com/bitcoin/@arunava/signalling-of-segwit2x-on-the-bitcoin-network-2017723t6310363z