Download true file name instead of from drupal version changed filename i have some file upload fields which works great. the file is stored on public file system and will be able to get downloaded from the users (in a specific node).

the issue is when i update the file (pdf) with a new version in the same month, drupal renames the file and save a new instance instead of updating the file (i know the reasons, avoiding global file conflicts on the page).

the user will download the renamed file which is wrong (e.g. manual_1.pdf). 
how can i change the filename into the name that is in its metadata (manual.pdf).

is there any hook, module or settings?
Is all depends on how your loading the file information. As the filename field in the file_managed table will always be whatever is uploaded. e.g.
filename = mypdf.pdf
uri = mypdf_1.pdf

So you can always use the filename value for the real file name. It sounds like whatever you're using to load the file/create the file link isn't using this correct value