2.6.0 backwards compatibility

jw schultz jw at pegasys.ws
Thu Jan 15 19:50:46 GMT 2004

On Thu, Jan 15, 2004 at 01:08:34PM -0500, Piela, Ben wrote:
> Hello all,
> I saw on the Release notes that 2.6.0 is using protocol version 27 which is
> different than 2.5.7 and 2.5.6.  I did a quick peak through the rest of the
> release notes and quickly browsed the archives on the list and I didn't see
> any notes on how well 2.6.0 works with older versions of rsync.  At our
> site, we do have 2.5.7 and 2.5.6 installed.  Are there any documented
> problems when using 2.6.0 with a down revved version on another system?

The code is designed to allow backward compatability. 
When a newer version is communicating with an older the will
use the highest common protocol version.  We do limit the
backwards compatability somewhat and will exit with an
error if you try to connect between incompatible versions.
Beginning with 2.6.0 there is also a warning if connecting
to a version that may not be supported by the next

In addition to the protocol errors there may be newer
command-line options so if you are using a new client and
try to use a command-line option not supported by an older
server the server will exit with an error message.

For the most part you don't need to worry about the protocol
versions.  On the other hand in addition to feature
enhancements, over time we fix bugs and improve performance
and if you do have problems only limited support is given to
older versions.

As for your situation 2.5.6 and 2.5.7 are not that old.
Some distributions are still shipping much older versions.

	J.W. Schultz            Pegasystems Technologies
	email address:		jw at pegasys.ws

		Remember Cernan and Schmitt

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