README.md in petrarca-0.4.0 vs README.md in petrarca-0.4.1

@@ -10,9 +10,11 @@
 All functions support both ISBN-13 and ISBN-10.
 
 All ranges of registration groups and registrants are supported.
 Those depends on 'RangeMessage.xml' file, downloaded from [International ISBN Agency](https://www.isbn-international.org/range_file_generation).
 
+note: Updated to latest version on January 12, 2021.
+
 ## Installation
 
 Add this line to your application's Gemfile:
 
 ```ruby