Changing the static map over time

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Hello, I have been trying to publish a map more than once but the trick is that the map image file is overwritten over time so I need map server to publish the new map and I did that by changing the source code of the map server node and now it keeps publishing as I wanted but rviz fails to show the map published. I tried to change the frequency of publishing and nothing worked. So how can I make it work? My guess is that rviz subscribes to the map topic once only.