On Sun, Nov 1, 2015 at 6:46 PM, Tier Nolan via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> For guidelines
>
> * Transaction version numbers will be increased, if possible
> * Transactions with unknown/large version numbers are unsafe to use with
> locktime
> * Reasonable notice is given that the change is being contemplated
> * Non-opt-in changes will only be to protect the integrity of the network
>
> Locked transaction that can be validated without excessive load on the
> network should be safe to use, even if non-standard.
>
> An OP_CAT script that requires TBs of RAM to validate crosses the
> threshold of reasonableness.
>

I like those guidelines, although I'm sure there may be lots of arguing
over what fits under "protects the integrity of the network" or what
constitutes "reasonable notice" (publish a BIP at least 30 days before
rolling out a change? 60 days? a year?)

-- 
--
Gavin Andresen