If pg_upgrade reports that a postmaster is servicing the cluster, please stop all Advanced Server services and try the upgrade again. See Step 4 in , Upgrading to Advanced Server 9.6 for detailed information about stopping a service.If pg_upgrade reports an authentication error that references a missing password, please modify the pg_hba.conf files in the old and new cluster to enable trust authentication, or configure the system to use a pgpass.conf file. See Step 3 in , Upgrading to Advanced Server 9.6 for detailed information about editing the pg_hba.conf file.If pg_upgrade reports that the new cluster is not empty, please empty the new cluster. For details about providing an empty target cluster, see Step 2 in , Upgrading to Advanced Server 9.6. Please note: the target cluster may not contain any user-defined databases.If the original Advanced Server cluster included libraries that are not included in the Advanced Server 9.6 cluster, pg_upgrade will alert you to the missing component during the consistency check by writing an entry to the loadable_libraries.txt file in the directory from which you invoked pg_upgrade.In the example shown, the old cluster contains PostGIS, while the new installation does not. Generally, for missing libraries that are not part of a major component upgrade, perform the following steps:Use StackBuilder Plus to download and install the missing module as described in Chapter 4, Using StackBuilder Plus.
4. Please Note: Advanced Server (version 9.2 and later) is compatible with PostGIS 2.3. For detailed instructions about upgrading to PostGIS 2.3, see Section 7.13.1.