On an upgrade from D7, I get the message:
- Transliteration has been merged into core. Fix existing file names.
At the linked page (admin/config/media/file-system/transliteration) it says:
Are you sure you want to transliterate existing file names?
WARNING: if you have manually entered image or file paths in text fields (for example, text areas or WYSIWYG editors), renaming the files will break these references. Since there is currently no automated way to also fix referenced files in textual contents, it is a very good idea to backup the database and directory beforehand. Modules accessing files using their internal system ids are not affected.
So if I am understanding, this is saying that the filename transliteration can be done automatically but then any existing links to these files within the site will be broken. Is there a best known method for finding and fixing those links?
Alternatively, is it necessary to do the transliteration or can I just leave it as it is?
I believe that's partially correct. Only paths you've entered manually in textareas or text boxes will point at the wrong file name. If you have file fields in your nodes for managed files (i.e. those you use the file field widget to upload), those shouldn't be affected - but I'd have to test this.
That, I don't know.