diff --git a/README.md b/README.md
index 8ecca02..287a81e 100644
--- a/README.md
+++ b/README.md
@@ -16,6 +16,7 @@ Current feature list
 * Delete folders
 * File upload
 * File download
+* pdf file reader using user provided pdf.js server
 
 Planned feature list
 
@@ -23,6 +24,8 @@ Planned feature list
 
 This app is a work in progress, so it have some bugs that need to be fixed
 
+You need to setup a pdf.js server to use pdf viewer. Just download latest version from official website and upload to any web server with ssl on same root domain than S3 server (can be same subdomain or a different one). Then set url to pdfjs root folder like https://example.com/pdfjs-dist
+
 Supported languages
 
 * English