when i try to backup user man with this cmd

[admin@MikroTik] tool user-manager> /
[admin@MikroTik] > /tool user-manager database save
no such command or directory (database)

I'm getting this error..

please help

Which version are you using?

currently user manager is on 2.9.27 i want to shift all users to another 3.23 server
what i will have to do?

Please, upgrade your router to 3.23 version. There is no database backup in v2.9.