I think T-Rex means the extra blocksize space

Actual Segwit activation happens at block 481824, according to achow101 above. From there on, people can start using 4MB of blocksize, but only if they're sending to a Segwit address. That will happen before the end of this week, I think around Wednsday or Thursday.

So, you can expect Bitcoin service providing companies (exchanges and larger retailers) to roll out the ability to send to Segwit addresses pretty quick, both to use business2-business and customer-2-business. But regular users need to start using Segwit addresses too, and that takes as long as it takes, no one can force people to do it (the old addresses still work just fine). Miners may begin to incentivise this by prioritising Segwit transactions more, but they already prioritise on the basis of transaction size, so any Segwit incentive would have to be over and above the existing fee per kB logic. All that will take between weeks and months to play out, possibly longer for the last P2PKH addresses to finally move to P2WPKH (the Segwit address/script type).

In addition, there's another BIP out there (171 i think?) that adds a new Segwit specific address format (current practice will be to use Segwit via P2SH addresses). This will be a whole extra new Segwit rollout of sorts. Hopefully, it will be tested and finalised for 0.15.1 (but I'm not at all sure on the specifics, that's just my ideal scenario). This will only add weeks and months to the overall switchover period, but bech32 (the name for the tech behind this new format) has alot of advantages.


Lightning? I expect we can see some test channels running quickly after activation of Segwit, but I think the software clients are still in development even now. Anyone know some more?