[Dovecot] Upgrading 1.2.17 -> 2.1.x

[Timo Sirainen]

On 9.6.2012, at 0.53, Adam G Tilghman wrote:

> 
> We're planning to upgrade our site from 1.2.17 to 2.1.x within the
> next few months, but we must ensure our ability to revert to 1.2.17
> if problems arise.
> 
> I don't expect our maildir storage would present a problem,
> but am less certain about 2.1.x index/control files remaining
> readable under 1.2.17.
> 
> Should I have any reason to worry?

1.2.17 can read v2.0 indexes without problems (it has some forwards compatibility code). I don't think I added any incompatible changes to v2.1 either, at least nothing major..