This seeks to clarify this diff since I fail to understand your edit comment. Note that MediaWiki master is now at 1.37+. Your change means that the extension caters for MW 1.35, 1.36 and 1.37? Not sure if this is meant but it will be cool if this is correct I believe.
Topic on Extension talk:AWS
The extension itself uses "master" compatibility policy, meaning that it maintains backward compatibility with MediaWiki 1.35. Its repository has REL1_34 branch that supports 1.27-1.34.
Cool, thanks for clarifying.