Dell has been somewhat slow in adopt new versions of Ubuntu. Currently, most of Dell’s Ubuntu computers offer 8.04, which was the last long term support release. Dell has changed their minds, though, at least for netbooks, which will soon offer 9.04, the latest release.
Previously, Dell had said they planned to use only the LTS (long term support) releases, since they are supposed to be more stable and are updated and given support for a much longer period of time. It is not yet clear if the decision to upgrade all netbooks to 9.04, which is not an LTS release, will also apply to any other Ubuntu computers.
Dell’s policy on Ubuntu versions has been, and remains to be, confusing. The official word has been that they would stick to 8.04 until the next LTS arrived. The Inspiron 15n, though, currently ships with 8.10. Now it looks like some of the computers will ship with 9.04. In other words, Dell will be supporting three different versions of Ubuntu.