i took backup before updating my server edition. After updating i have to use my backup business.manager files to open with desktop edition and create users. once you create users or use your backed up business.manager file with newer version of desktop edition or server edition , you cant revert back to older version.
i faced few problems with the newer version of server edition (17.5.0) like multi user (which was much simpler for me in older version)
At a point i decided to go for cloud edition. but it showed message saying that my backup business.manager file accessed latest version so i cant use old version (cloud edition is 17.3.20).
then i realised i have all my files in AppData folder in my server so i jusr installed 17.3.0 server edition. and it worked perfectly. and all my old options are available same as before.
Thank you @lubos for your support.