Kevin Cheng wrote:
Upgrade code based on release of obsd is easy, but it would a big job to maintain early released of products based on previous version of obsd. For example, we would maintain 8 version of products from 3.3 to 4.0 if codesare upgraded every half years.
Why? If you do an OS upgrade it leaves the old shared libraries around, so any installed apps should continue working. If you want OS version independence, then compile your app static.