F18 - compatibility problem between postgresql and postgis

Hi,

i encounter a problem upgrading Fedora from 17 to 18

i need to Upgrade Postgresql from 9.1 to 9.2

For doing so i run

postgresql-setup upgrade

with some trust in place of md5 in pg_hba.conf and .pgpass file with option PGPASSFILE in script postgresql-setup to connect easily to database

In /var/lib/pgsql/pg_upgrade.log i get :

Performing Consistency Checks
-----------------------------
Checking current, bin, and data directories ok
Checking cluster versions ok
Checking database user is a superuser ok
Checking for prepared transactions ok
Checking for reg* system OID user data types ok
Checking for contrib/isn with bigint-passing mismatch ok
Creating catalog dump ok
Checking for presence of required libraries fatal

Your installation references loadable libraries that are missing from the
new installation. You can add these libraries to the new installation,
or remove the functions using them from the old installation. A list of
problem libraries is in the file:
loadable_libraries.txt

Failure, exiting



Looking at loadable_libraries.txt i get :

Could not load library "$libdir/postgis-1.5"
ERROR: incompatible library "/usr/lib/pgsql/postgis-1.5.so": version mismatch
DETAIL: Server is version 9.2, library is version 9.1.

It seems to be an incompatibility between postgis-1.5.3-4.fc18.i686 and postgresql-9.2.2-1.fc18.i686

i saw an analogous message on Internet 10 days ago

What should be the issue ?

Cheers