The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/9.5/static/sql-createuser.html
Description:
The CREATE USER doc still states SYSID can be specified although I obtained:
SYSID can no longer be specified
while using the following command:
CREATE USER someuser WITH LOGIN ENCRYPTED PASSWORD 'somepwd' SYSID 1000;
I guess the documentation is outdated.