The fallow period sounds waaaay to short. I suggest 2 months at minimum
since anyone that wants to be safe needs to upgrade.
Also, please comment on why you won't use the much more safe and much
smaller Flexible Transactions.
On Sunday, 16 October 2016 16:31:55 CEST Pieter Wuille via bitcoin-dev
> Hello all,
> We're getting ready for Bitcoin Core's 0.13.1 release - the first one
> to include segregated witness (BIP 141, 143, 144, 145) for Bitcoin
> mainnet, after being extensively tested on testnet and in other
> software. Following the BIP9 recommendation  to set the versionbits
> start time a month in the future and discussion in the last IRC
> meeting , I propose we set BIP 141's start time to November 15,
> 2016, 0:00 UTC (unix time 1479168000).
> Note that this is just a lower bound on the time when the versionbits
> signalling can begin. Activation on the network requires:
> (1) This date to pass
> (2) A full retarget window of 2016 blocks with 95% signalling the
> version bit (bit 1 for BIP141)
> (3) A fallow period consisting of another 2016 blocks.
>  https://github.com/bitcoin/bips/blob/master/bip-0009.mediawiki
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