ERROR: incompatible library

Hello lists,

I am trying to run Slony on a Master Postgres 8.1.11 replicating to a
Slave same version and 2nd Slave Postgres 8.3.4.

The purpose is to update Postgres in production by steps, first slaves
then switchover to upgrade the master that will not be master when
upgraded.

I am getting the following error:

<stdin>:14: PGRES_FATAL_ERROR load '$libdir/xxid'; - ERROR:
incompatible library "/usr/lib/pgsql/xxid.so": missing magic block

HINT: Extension libraries are required to use the PG_MODULE_MAGIC
macro.

<stdin>:14: Error: the extension for the xxid data type cannot be loaded
in database 'dbname=hdap host=10.0.100.234 port=6543 user=myuser
password=mp'

Is this mean that Slony can not replicate into a newer postgres version?

If it does, then how do I fix this problem?

Thanks for your help,

Tony Fernandez