[bitcoin-dev] Planned Obsolescence

[Jorge Timón]

On Thu, Dec 15, 2016 at 4:38 AM, Juan Garavaglia via bitcoin-dev
<bitcoin-dev at lists.linuxfoundation.org> wrote:
> Older node versions may generate issues because some upgrades will make
> several of the nodes running older protocol versions obsolete and or
> incompatible. There may be other hard to predict behaviors on older versions
> of the client.

Hard to predict or not, you can't force people to run newer software.

> In order to avoid such wide fragmentation of "Bitcoin Core” node versions
> and to help there be a more predictable protocol improvement process, I
> consider it worth it to analyze introducing some planned obsolescence in
> each new version. In the last year we had 4 new versions so if each version
> is valid for about 1 year (52560 blocks) this may be a reasonable time frame
> for node operators to upgrade. If a node does not upgrade it will stop
> working instead of participating in the network with an outdated protocol
> version.

When you introduce anti-features like this in free software they can
be trivially removed and they likely will.

> These changes may also simplify the developer's jobs in some cases by
> avoiding them having to deal with ancient versions of the client.

There's a simpler solution for this which is what is being done now:
stop maintaining and giving support for older versions.
There's limited resources and developers are rarely interested in
fixing bugs for very old versions. Users shouldn't expect things to be
backported to old versions (if developers do it and there's enough
testing, there's no reason not to do more releases of old versions, it
is just rarely the case).