From https://reference.wolfram.com/language/guide/SummaryOfNewFea...
New in machine learning in 13.1 ...
ContentDetectorFunction (updated) — support for Information DimensionReducerFunction(updated) ▪ FeatureExtractorFunction(updated) FindClusters (updated) — support for fixed number of clusters and UpTo ClusterClassify(updated) ▪ ClusteringComponents(updated) Interpretable Machine Learning FeatureValueImpactPlot — plots the impact of a feature on a model result FeatureImpactPlot — plots the impact of each feature together CumulativeFeatureImpactPlot — plots the cumulative impact of each feature FeatureValueDependencyPlot — plots the result dependency on a feature value Network Layers » ReplicateLayer (updated) — support for integer arrays RandomArrayLayer (updated) — support for more statistical distribution AttentionLayer (updated) — support for dropout and local masking ElementwiseLayer (updated) — new activations "Mish" and "GELU" ThreadingLayer(updated) ▪ FunctionLayer(updated) Network Training » NetTrain (updated), LossFunction (updated) — support for multi-output and nonscalar loss Encoders & Decoders » "Image" (updated) — resampling and padding support "Class" (updated) — support for top-k and top-p sampling (nucleus sampling) Formats "ONNX" (updated) — export support for net operators