My problem is some heavily customised code mixed in with OpenACS 4.6.1. I want to upgrade to OpenACS 5.0 but am dreading doing it because of my changes and customisations. I had hoped to try installing two instances of postgres as a temporary measure but the environment variables that postgres requires will make that impossible (i.e. cannot point LD_LIBRARY_PATH to two places at once can I!?).
Maybe the best thing is to go for 7.3.4 on what is planned to be the production machine and try to upgrade to 7.4 on the development box.
If I wanted to avoid messing with any of my custom code in the photo album and ecommerce modules, what would be the minimum partial upgrade necessary to move a site from 4.6.1 to 4.6.3 so that it will run with Postgres 7.4?