by Rick Jerz.
In general, I try to upgrade my experimental site first, see what happens, then I update my production site. Usually, upgrades within a dot.dot version, like from 2.4.2 to 2.4.3 are quite good. However, I find it real important to test the first dot increases, for example, from 2.3 to 2.4. There were some surprises that I had to take care of before upgrading my production server.
For major version upgrades, such as version 1 to 2, well... lots of testing. I actually did a brand new install when Moodle 2.0 came out.
