[tor-bugs] #22251 [Core Tor/Tor]: Time to not require Tor relays to support old link versions? (was: Time to retire old link versions?)

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#22251: Time to not require Tor relays to support old link versions?
--------------------------+------------------------------------
 Reporter:  arma          |          Owner:
     Type:  enhancement   |         Status:  new
 Priority:  Medium        |      Milestone:  Tor: 0.3.2.x-final
Component:  Core Tor/Tor  |        Version:
 Severity:  Normal        |     Resolution:
 Keywords:                |  Actual Points:
Parent ID:                |         Points:
 Reviewer:                |        Sponsor:
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Old description:

> In our spec, we have
> {{{
>    All new relay implementations of the Tor protocol MUST support
>    backwards-compatible renegotiation
> }}}
>
> But the v3 link handshake came out in Tor 0.2.3.6-alpha. That's certainly
> older than any relays. Is it older than any clients that we expect to
> work?
>
> Step 0 in phasing out old link versions would be to admit in tor-spec
> that supporting them is not a MUST. I'd say we're ready to do this one
> any time. We could put v3 as the minimum you MUST implement, or we might
> pick v4, since it came out in 0.2.4.11-alpha, and that's pretty old now
> too.
>
> Step 1 in phasing out old link versions would be to actually remove the
> code from mainline Tor. In preparation, we should try to figure out which
> Tor client versions are still in use today, and which ones still happen
> to work with the current network, and figure out in what time frame we'll
> be ok breaking those old Tor clients.

New description:

 In our spec, we have
 {{{
    All new relay implementations of the Tor protocol MUST support
    backwards-compatible renegotiation
 }}}

 But the v3 link handshake came out in Tor 0.2.3.6-alpha. That's certainly
 older than any relays. Is it older than any clients that we expect to
 work?

 Step 0 in phasing out old link versions would be to admit in tor-spec that
 supporting them is not a MUST. I'd say we're ready to do this one any
 time. We could put v3 as the minimum you MUST implement, or we might pick
 v4, since it came out in 0.2.4.11-alpha, and that's pretty old now too.

 Step 1 in phasing out old link versions would be to actually remove the
 code from mainline Tor. That's #9476.

--

Comment (by arma):

 In light of #9476, I'm going to change this ticket to be only about the
 spec change.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/22251#comment:4>
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