For the purpose of this appendix, an "incompatibility" is defined to be a part of the product that works differently than it did in the previous release, in such a way that if used in an existing application, it will produce a different result, necessitate a change to the application, or reduce performance. In this definition, "application" can apply to a broad range of things (singly or in combination), such as:
This appendix does not describe incompatibilities where certain operations in the current release are less likely to generate an error condition than they did in the previous release, as those changes will only have a positive impact on your applications. (For example, the SUM and AVG column functions no longer overflow as easily because they now use a larger accumulator, and a change to the use of the equal (=) compare predicate with a negative indicator variable now evaluates to UNKNOWN rather than generating an error condition.)