This file contains a summary of important user-visible changes. 

Changes since 1.4
=================

* Support for unsat cores.
* Simplification mode "incremental" no longer supported.
* Support for array constants in constraints.
* Syntax for array models have changed in some language front-ends.
* New input/output languages supported: "smt2.0" and "smtlib2.0" to
  force SMT-LIB v2.0; "smt2.5" and "smtlib2.5" to force SMT-LIB v2.5.
  "smt", "smtlib", "smt2", and "smtlib2" all refer to the current standard
  version 2.0.  If an :smt-lib-version is set in the input, that overrides
  the command line.
* Abstract values in SMT-LIB models are now ascribed types (with "as").
* In SMT-LIB model output, real-sorted but integer-valued constants are
  now printed in accordance with the standard (e.g. "1.0").

Changes since 1.3
=================

* CVC4 now supports libc++ in addition to libstdc++ (this especially
  helps on Mac OS Mavericks).
* The LFSC proof checker has been incorporated into CVC4 sources.
* Theory of finite sets, handling the MLSS fragment (singleton, union,
  intersection, set subtraction, membership and subset).
* By default, CVC4 builds in "production" mode (optimized, with fewer
  internal checks on).  The common alternative is a "debug" build, which
  is much slower.  By default, CVC4 builds with no GPL'ed dependences.
  However, this is not the best-performing version; for that, you should
  configure with "--enable-gpl --best", which links against GPL'ed
  libraries that improve usability and performance.  For details on
  licensing and dependences, see the README file.
* Small API adjustments to Datatypes to even out the API and make it
  function better in Java.
* Timed statistics are now properly updated even on process abort.
* Better automatic handling of output language setting when using CVC4
  via API.  Previously, the "automatic" language setting was sometimes
  (though not always) defaulting to the internal "AST" language; it
  should now (correctly) default to the same as the input language
  (if the input language is supported as an output language), or the
  "CVC4" native output language if no input language setting is applied.
* The SmtEngine cannot be safely copied with the copy constructor.
  Previous versions inadvertently permitted clients to do this via the
  API.  This has been corrected, copy and assignment of the SmtEngine
  is no longer permitted.

Changes since 1.2
=================

New features:
* SMT-LIB-compliant support for abs, to_real, to_int, is_int, which were
  previously missing
* New bv2nat/int2bv operators for bitvector/integer inter-compatibility.
* Support in linear logics for /, div, and mod by constants (with the
  --rewrite-divk command line option).
* Parsing support for TPTP's TFF and TFA formats.
* A new theory of strings: word (dis-)equations, length constraints,
  regular expressions.
* Increased compliance to SMT-LIBv2, numerous bugs and usability issues
  resolved.
* New :command-verbosity SMT option to silence success and error messages
  on a per-command basis, and API changes to Command infrastructure to
  support this.

Behavioral changes:
* It is no longer permitted to request model or proof generation if there's
  been an intervening push/pop.
* User-defined symbols (define-funs) are no longer reported in the output
  of get-model commands.
* Exit codes are now more standard for UNIX command-line tools.  Exit code
  zero means no error---but the result could be sat, unsat, or unknown---and
  nonzero means error.

API changes:
* Expr::substitute() now capable of substituting operators (e.g.,
  function symbols under an APPLY_UF)
* Numerous improvements to the Java language bindings

Changes since 1.1
=================

* Real arithmetic now has three simplex solvers for exact precision linear
  arithmetic: the classical dual solver and two new solvers based on
  techniques for minimizing the sum of infeasibilities. GLPK can now be used
  as a heuristic backup to the exact precision solvers.  GLPK must be enabled
  at configure time. See --help for more information on enabling these solvers.
* added support for "bit0" and "bit1" bitvector constants in SMT-LIB v1.2
* support for theory "alternates": new ability to prototype new decision
  procedures that are selectable at runtime
* various bugfixes

Changes since 1.0
=================

* bit-vector solver now has a specialized decision procedure for unsigned bit-
  vector inequalities
* numerous important bug fixes, performance improvements, and usability
  improvements
* support for multiline input in interactive mode
* Win32-building support via mingw
* SMT-LIB get-model output now is easier to machine-parse: contains (model...)
* user patterns for quantifier instantiation are now supported in the
  SMT-LIBv1.2 parser
* --finite-model-find was incomplete when using --incremental, now fixed
* the E-matching procedure is slightly improved
* Boolean terms are now supported in datatypes
* tuple and record support have been added to the compatibility library
* driver verbosity change: for printing all commands as they're executed, you
  now need verbosity level >= 3 (e.g., -vvv) instead of level 1 (-v).  This
  allows tracing the solver's activities (with -v and -vv) without having too
  much output.
* to make CVC4 quieter in abnormal (e.g., "warning" conditions), you can
  use -q.  Previously, this would silence all output (including "sat" or
  "unsat") as well.  Now, single -q silences messages and warnings, and
  double -qq silences all output (except on exception or signal).

-- Morgan Deters <mdeters@cs.nyu.edu>  Wed, 02 Jul 2014 14:45:05 -0400