If you use the same name for the feed file and simply update it, it may take upwards of 6 hours for Roku to recognize the changes. On a side note, depending on the amount of traffic, using your own web site may cause performance issues.
FREE Windows desktop software for converting Direct Publisher channels to SceneGraph (SDK), for creating
BIF (Trick Play) files,
Roku (MRSS, JSON) feed files, and
FireTV feed files @
GitHub/rrirower.