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