About the OCT... does it still exist? Where do they meet?
the OCT does not meet regularly since a while. We discuss from time to time things via email.
Is there an estimate, or at least an idea, of what would be the effeort required to move an application developed for previous versions of OpenACS to this new version?
We have not released a new version of OpenACS, but used the head version from CVS for openacs.org. Estimating in the effort to upgrade to the head version of OpenACS can't be answered in general, since there are many OpenACS installations out there, where some of these are based on very early OpenACS forks, or some have substantial local modifications.
For recent versions of OpenACS core (e.g. OpenACS 5.5 or newer), the upgrade is a no-brainer: as always, get the new openacs packages and run the upgrade scripts. We have a wiki page (https://openacs.org/xowiki/Postgres_9) for upgrading which contains more details, especially, if one wants to upgrade to pg9.
Using pg9 is highly recommended for large OpenACS installations, since it solves a long standing issue with performance of permission queries. Due to changes in the PostgreSQL optimizers, the performance of the permission queries for large installations degraded after pg 8.3, such that several installations could not upgrade to newer pg versions. For our production environment, we had to rewrite the permission queries using recursive queries (Victor did most of this) some time ago, which is now merged back into OpenACS. Another argument against pg 8.3 is that this is no longer supported by the pg community.
