That is a very good point. 

We considered whether data existing before a licence change would be covered, but we hadn't factored the potential need for gaining permissions for a change to be considered effective.

We have proposed that miners be the main beneficiaries of licensing and there is a consideration on whether they should vote to adopt the new terms. While not the preferred route, that would overcome any issues to what is an otherwise honest 'error and omission.' There doesn't seem to be anyone who could claim to have suffered any economic losses so this may not be an issue. It merits further investigation.

The block chain is in perpetual change, so the sooner a change is agreed upon, if at all, the more data it will cover without any reservations. At any rate, we believe the changes would be considered effective on a retrospective basis.


On Tue, Sep 1, 2015 at 7:12 PM, Btc Drak <btcdrak@gmail.com> wrote:
Without commenting on your proposal at all, the general problem with
licensing after the fact is you require the permission of every
copyright holder in order to make the change.



On Tue, Sep 1, 2015 at 2:30 PM, Ahmed Zsales via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> Hello,
>
> We believe the network requires a block chain licence to supplement the
> existing MIT Licence which we believe only covers the core reference client
> software.
>
> Replacing or amending the existing MIT Licence is beyond the scope of this
> draft BIP.
>
> Rationale and details of our draft BIP for discussion and evaluation are
> here:
>
> https://drive.google.com/file/d/0BwEbhrQ4ELzBMVFxajNZa2hzMTg/view?usp=sharing
>
> Regards,
>
> Ahmed
>
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