versions interoperability (Re: IRC 2.8.21 compilation)

[Christophe Kalt <kalt@xxxxxxxxxxx>]

On Nov 10, Graham_Gillies@xxxxxxxxxxx wrote:
|      I'm trying to compile the 2.8.21 IRCD.

pre 2.9.x version discussion isn't considered to be appropriate
for this list, however, i think the compatibility issues are
interesting.

|      The reason i'm using such a back level version is that the other IRC
| servers in the network are all 2.8 servers.

backward compatibility is somewhat tricky with IRC, and shows
a lot about the protocol shortcomings.  Basically, old and
recent versions cannot coexist peacefully, and the realities
of this have only been somewhat documented recently.

+ 2.9.3 (and later) cannot coexist on a network with 2.7
  servers (i forget why)
+ 2.9.4 (and later) no longer support 2.8 server links
+ most of 2.10.x new features are unavailable outside
  contiguous 2.10.x clouds in a network

I know there are many networks using rather ancient versions
of the IRC server software, and this is a problem for them as
there is no longer any supported software for these.
Basically, if you run a 5 year old irc server, you may very
well need to run it on a 5 year old OS and figure out things
mosly on your own.

i don't really know of any reason why someone would refuse to
upgrade server versions, but would be curious to hear of such
motives if they exist.  Really, i think the best way is to
upgrade the servers progressivly.

Christophe