The SAT4J team decided to release its fifth maintenance release of the 2.0 version of the library.

The major change for SAT users is a specific data structure for unit and binary clauses that reduces the memory footprint of the constraints in the solver while maintaining the possibility to apply reason simplification.

Note that the H/T data structure implementation is slightly slower than the Watched Literals data structure that was available up to release 2.0.3 (see the ModelIteratorTest for instance that used to pass within the given timeout that no longer pass now).

MAXSAT users are strongly encouraged to update to 2.0.5 since that release includes some bug fixes on corner cases with weighted unit clauses.

The release includes also minor changes (fixed messages displayed on the console, displaying information about learned clauses, etc).

We encourage all SAT4J users to update to that new release, that is likely to be the last one of the 2.0 version of the library.

All important new features (support for BigInteger weights in MAXSAT, explanation support, etc) is going to be released in the future 2.1 release.