Continuous Integration (CI) servers are critical in the creation of deterministic release cycles. Any long-term instability in the CI server will reflect in the milestones of your project plans. Incremental upgrading is addictive and mostly straightforward, but should be seen in the light of the Jenkins wider role.
Before the release of plugins into the world of your main development cycle, it is worth aggressively deploying to a sacrificial Jenkins instance, and then sitting back and letting the system run the Jobs. This gives you enough time to react to any minor defects found.
There are many ways to set up a sacrificial instance. One is to use a virtual image of Ubuntu and share the workspace with the