For those of you running newer routerOS versions you should be aware of this.
Downgrading to any version prior to v6.43 (v6.42.12 and older) will clear all user passwords and allow password-less authentication. Please secure your router after downgrading.
I am not sure when this actually started as it shows up in the changelog of 6.45beta62. I am going to assume this starts at 6.45 once it’s released.j2networks family of sites