Do cyrus devs plan to implement PUSH-IMAP protocol?

Greg Banks gnb at fastmail.fm
Mon Jan 30 21:32:41 EST 2012



On Mon, Jan 30, 2012, at 10:40 PM, Sébastien Michel wrote:
> >
> > Georg, I notice there's a page about Z-Sync on the Kolab wiki. Do you have
> > any idea of the legal issues with the protocol?
> >
> 
> Hard to find an answer, but below some useful links :

Thanks Sébastien!

> http://www.microsoft.com/about/legal/en/us/IntellectualProperty/IPLicensing/Programs/ExchangeActiveSyncProtocol.aspx

That page is less than entirely useful.  In summary: "ActiveSync exists, we own patents on it, talk to us".

> http://notes.kateva.org/2009/02/googles-activesync-license-interesting.html
> http://z-push.sourceforge.net/phpbb/viewtopic.php?f=4&t=113

These pages are both more or less entirely rumour and speculation.  However, one
contained a link to the Microsoft site which eventually proved interesting.

At this time I should point out that I'm not a lawyer.

It seems Microsoft have several different licence programs under which they licence
patent-encumbered protocols and file formats: Microsoft Interoperability Program,
Microsoft Communications Protocol Program, Workgroup Server Protocol Program,
and Interoperability Principles.  Some specifications are covered by multiple of these.

The different programs have different reasons for their existence.  Some exist as a
result of an antitrust decision against Microsoft, i.e. the company was compelled by
a court to open the protocols.  These smell pretty safe for us to use.  The protocols
that Samba uses are covered by such a licence program, and I've heard Tridge say
very complimentary things to Microsoft about their co-operation (once compelled by
the court).

The ActiveSync protocols however appear to be covered only by the weakest of the
licencing programs, which is described here

http://www.microsoft.com/openspecifications/en/us/programs/other/interoperability-principles-patent-pledges/default.aspx

On a careful but not lawyerly reading I note that

a) It's just a promise - there's no legal ruling enforcing it and nothing stopping
    Microsoft from going back on it at any time.  It's not even a licence.

b) It's a promise to the developer of open source software, either companies
    or individuals, and not to any users of that software.

c) There is some worrying wiggle room around what "open source licence"
    means. I'd guess that any licence listed at the Open Source Initiative is
    safe, as Microsoft have submitted some of their licences to the OSI,  The
    Cyrus licence isn't there, but it's very very similar to one of the BSD 
    licences that is there.  Z-Push is GPL and should be fine.

> >> Personally I'd be strongly in favour of such technologies.
> >
> >
> > Me too; I work with an iOS device and a Cyrus server daily. Lots of our
> > customers use iOS devices.
> >
>  pity it is a poorly written IMAP client. It doesn't support well IMAP
> standards.

Possibly, but it is ubiquitous.

> Here's a tip:) it supports IMAP SPECIAL-USE, but *only* in response to
> the non-extended IMAP LIST command. The workaround is easy to code in
> Cyrus

Cool!  Have you coded it yet?  I don't see a Bugzilla ticket.

-- 
Greg.


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