This is certainly a general core issue affecting all uploaded documents. I've tested both versions: Joomla 5.2.6 and the updated Joomla 5.3. In both versions, the "File URL" field in the configuration - individual document details - is not set (empty). While in the older version of Joomla 5.2.6, the file is found by Edocman 2 (the file size is correctly displayed in KB on the website in the details), in Joomla 5.3, no document is found, and the size is not displayed.
In the version of Edocman 2 with Joomla 5.2.6, the file download starts correctly when I click on the document file (Current File) in the configuration details of each document. However, in the updated version with Joomla 5.3, after clicking on the name of the current file, I'm kicked out of the Edocman configurations and landed in the Joomla dashboard.
In my opinion the default URL setting has changed in the new Joomla 5.3 and the URL is no longer recognized in Edocman 2.
ATTENTION: In Joomla 5.3 I notice that in the Main Configuration the "Documents Path" field is indicated in red as "Documents Path is not writable"!
. I checked the two edocman folders (edocman and edocmanviewer, as well as their subfolders) on the website individually in Joomla 5.3. They are all set with the correct permissions of 755 (just like in Joomla version 5.2.6).