The main thrust has been documentation. However, some bug fixes and other changes have also been made in this release of 15 may 2009:

• Modified ParetoFrontPlot and ParetoFrontLogPlot so that any EnsemblePersonality settings will be used as options.
• Changed the default SimplificationFunction for ModelSelectionReport and ModelSelectionTable to be None. It turns out that Simplify (which was the previous default) will convert integers into reals AND insert a multiplier of 1.0 for variables if it detects a real-valued number in the expression. Since models will generally feature the scaling & translation factors as a result of being automatically aligned as a last processing step in SymbolicRegression, this produces quite a bit of visual clutter which would not be present if we simply looked at the ModelExpression.
• Modified ModelSelectionReport and ModeleSelectionTable so that the EnsemblePersonality will be supplied as options.
• Modified EvaluateModel EvaluateEnsemble, EvaluateEnsemblePrediction, EvaluateEnsembleDivergence, EnsembleResidual and ModelResidual so that if a vector of evaluation points (rather than a matrix) is supplied and there is only a single DataVariables symbol defined, it will recognize that the supplied vector is a list of evaluation points rather than a single evaluation point (which is the behavior, otherwise).
• Fixed a bug in EnsembleResidualPlot so that it now can handle a vector of evaluation points. Also, made the default PlotRange -> All rather than Automatic.
• Modified EnsembleResidualPlot so that VariablesToPlot may be set to None. If this is done (and IncludeResponse -> True) then only the residual of the observed behavior will be plotted.
• Fixed a sin-of-omission in CreateFittedEnsemble wherein supplied options were not being automatically inserted into the returned EnsemblePersonality. The behavior is now consistent with that of CreateModelEnsemble.
• Removed support for the KickoutFunction option for EvaluateModel, EvaluateGenome, etc. since the default behavior of $NumericCompileKickoutFunction returning Indeterminate is probably fundamental to a successful SymbolicRegression because of the built-in support for Indeterminate. $NumericCompileKickoutFunction is unprotected so it can be changed and the output of NumericCompile whenever machine precision is left will be adjusted accordingly.
• Modified DivergenceSurfacePlot so that it recognizes GPModel input as well as ModelEnsemble and produces a nice looking graphic saying that the divergence surface of an individual model is meaningless.
• Fixed a bug in ModelSelectionReport wherein supplied formatting options (e.g., FontSize -> Large) were not getting transferred to the header row of the report table. Unfortunately, ModelSelectionTable will need more extensive modification to allow for entry formatting.
• Fixed a bug in BalanceData and BalanceDataIndices where the some of the most important data records would (occassionally) not be returned.