Publish problem

I have a problem when i try to publish the app ,
every time i would to publish it , i should delete the previous version and publish the new version to work !!

why ??

why should i delete the previous version instead of publish only the changed !!

anyone else faced this problem ?

In Publish Settings depending on what Publish Method you use there is File Publish Options
Is "Delete All existing files prior to publish" ticked ?

sorry , i talk about upload the published app on the server ,
there is a problem on the server that i should remove the previous version on the server

Do you mean you make changes and they are not recognised so you delete the website and then the changes work
Maybe you need to stop and start the server / Clear the cache / restart the application rather than delete

yes i mean that , i'll try this solution ..

Thank you