On March 1, we're going to disable and start removing the "old" classifiers. If you're still using them at that time your scripts will throw an error.
The classifiers that are being removed, and their replacements are:
Classifier.cart -> Classifier.smileCart
Classifier.randomForest -> Classifier.smileRandomForest
Classifier.naiveBayes -> Classifier.smileNaiveBayes
Classifier.svm -> Classifier.libsvm
All of these have also been deprecated and will also be removed at that time.
Classifier.continuousNaiveBayes
Classifier.gmoLinearRegression
Classifier.ikpamir
Classifier.pegasosLinear
Classifier.pegasosGaussian
Classifier.pegasosPolynomial
Classifier.perceptron
Classifier.winnow
-- Noel Gorelick
and the Earth Engine Team