Hi, we confirm that passwords have never been stored in plain text. However, there was a security concern when sending passwords by email.
— PrestaShop (@PrestaShop) December 12, 2018
Note that this issue has been fixed in 1.6.1.18 and also in 1.7.
More information below. :) https://t.co/zBocDGUiw2
https://goo.gl/EO0ad1
https://goo.gl/xF8heB