  The purpose of this note is to discuss some aspects of recently proposed
fractional-order variants of complex least mean square (CLMS) and normalized
least mean square (NLMS) algorithms in ``Design of Fractional-order Variants of
Complex LMS and Normalized LMS Algorithms for Adaptive Channel Equalization''
[Nonlinear Dyn. 88(2), 839-858 (2017)]. It is observed that these algorithms do
not always converge whereas they have apparently no advantage over the CLMS and
NLMS algorithms whenever they converge. Our claims are based on analytical
reasoning and are supported by numerical simulations.
