Not possible to remove mysql user password

When editing a mysql user via Webmin -> Servers -> MySQL Database Server -> User Permissions
An setting the password to ‘None’, an error is shown:
“Failed to save user : SQL update user set password = NULL where user = ? and host = ? failed : Unknown column ‘password’ in ‘field list’”

Should probably be “update user set authentication_string = NULL where user = ? and host = ?”

Operating system Ubuntu Linux 16.04.4
Webmin version 1.881
Usermin version 1.741
Virtualmin version 6.02-3
MySQL version 5.7.21