I host a ATOM feed (through my ERP software). User subscribes to the feed in Outlook. I will publish new content once in 24 Hrs. So I like the users have only the feeds published today in his Outlook (not to have old posts published yesterday and has to be removed from outlook). Is this achievable with some settings in outlook or configuration/parameter of Feeds changes in server side?
No, there's no way to force a feed reader to hide older items. Documentation suggests that Outlook can be configured to discard older items - Automatically delete older RSS items. As long as you're only serving up entries from the last 24 hours and Outlook is deleting anything more than 24 hours old you should get the behaviour you want.