If you already run an older version of RefDB and want to upgrade to the latest version, you may have to change a few things in your local setup in order to reuse existing databases and existing configuration files. This section lists all backwards-incompatible changes of the past few versions (the complete list since the days of yore can be found in the file README).
The file UPGRADING contains instructions how to avoid losing your data in the case of non-trivial changes in the new version.
Major changes in both the reference databases and the main database require to upgrade both.
Before re-importing your reference data, you may have to migrate the contents of some AV fields to L1
Before re-importing custom citation styles, you may have to fix a few elements. The styles shipped with RefDB do not require these fixes, you can just add them again.
The implementation of personal reference lists has changed, most notably in that each user can have more than one of these lists. Although there was no need to alter the database schema, one of the tables is now used to record the ownership of a reference instead of the membership of a reference in a personal list. The results may be a bit unexpected if you upgrade to 0.9.8 without migrating the data.