IEC 60601-2-66:2019 is available as IEC 60601-2-66:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60601-2-66:2019 applies to the BASIC SAFETY of HEARING AIDS and HEARING AID SYSTEMS, hereafter also referred to as ME EQUIPMENT or ME SYSTEM. IEC 60601-2-66:2019 cancels and replaces the second edition published in 2015. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) revision of the definition about ESSENTIAL PERFORMANCE;
b) revision of the application of IEC 60601-1-2:2014 for electromagnetic disturbances;
c) correction of the used voltage for HEARING AIDS from 1,6 V to 4,5 V;
d) correction of the drop test level from 1,5 m to 1,0 m;
e) correction of the wording of IEC 60601-2-66:2015.