Hello syasinba,
an item of a digest is updated if at least one of the following fields if its source feed's item has been changed:
1) Title
2) Link
3) PubDate
4) Description
Please also note that digest updates only when FI robots revisit its source feed, i.e. do not expect that digest will be updated immediately after the source feed has been edited. Typically it takes up to 40 minutes (max) to update a digest, though it might get updated even in one minute.

Hi All,

I am using Feed informer form long time.

I chose "javascript" format to display on site. It is displaying properly on the site.
But when I modified description or changed some text that feed it is not updating, It is displaying same old feed rather than updated(modified content) one.