Unable to upgrade from 12.7 to 15.2

Hello All,

we are facing below issues while upgrading the cluster from 12.7 to 15.2.

The OLD cluster contains cstore_fdw extension and we have installed
Citus(updated version of cstore_fdw) in postgresql 15.2 , we are not able
to proceed further as the below error is the blocker for the same, any help
regarding this will be much helpful.

TESTHOST:/tmp $ $NEW_PG_PATH/bin/pg_upgrade -b $OLD_PG_PATH/bin/ -B
$NEW_PG_PATH/bin/ -d $OLD_PG_DATA -D $NEW_PG_DATA --check
Performing Consistency Checks
-----------------------------
Checking cluster versions ok
Checking database user is the install user ok
Checking database connection settings ok
Checking for prepared transactions ok
Checking for system-defined composite types in user tables ok
Checking for reg* data types in user tables ok
Checking for contrib/isn with bigint-passing mismatch ok
Checking for user-defined encoding conversions ok
Checking for user-defined postfix operators ok
Checking for incompatible polymorphic functions ok

New cluster database "postgres" is not empty: found relation
"columnar_internal.options"
Failure, exiting

Thanks,
Mahesh.