When I upload new webpage to server can i just change folder's name?

i am making new webpage in these days.

i am using editplus with sftp and filezilla.

and the server is centOS.

there is a one folder named "foo" assigned to www.example.com

and there is a folder that i been working on named "foo_dev".

both folder have same permission properties.

so I thought that it will be fine to change "foo" to "foo_original"

and "foo_dev" to "foo". but my senior said this is not correct way.

and i learned that git or any version control system can be applied

in the web development too, but he doesn't want it.

what is the simple and best way to upload changes?