Historically, three energy flow packages have been used in ALEPH: the mask algorithm of M-N. Minard and M. Pepe-Altarelli, the PCPA-based energy flow of A. Bonissent, and the ENFLW package of P. Janot. Since ALPHA 115 (May 1993), the ENFLW package is fully integrated in ALPHA; all features of the other two packages are not maintained any more. Therefore, users are strongly advised to use the ENFLW energy flow.