The supplied dates indicate when the API change was made, on the HG default branch. From this you can generally tell whether the change should be present in a given build or not; for trunk builds, simply whether it was made before or after the change; for builds on a stabilization branch, whether the branch was made before or after the given date. In some cases corresponding API changes have been made both in the trunk and in an in-progress stabilization branch, if they were needed for a bug fix; this ought to be marked in this list.
Fuller descriptions of all changes can be found below (follow links).
Not all deprecations are listed here, assuming that the deprecated APIs continue to essentially work. For a full deprecation list, please consult the Javadoc.
These API specification versions may be used to indicate that a module requires a certain API feature in order to function. For example, if you see here a feature you need which is labelled 1.20, your manifest should contain in its main attributes the line:
OpenIDE-Module-Module-Dependencies: $codebase > 1.20
Sampler; made by: thurka