Amazon perceives Opera as not up to date and produces this message:
This website works best in Firefox 31+, Chrome 36+, Internet Explorer 9+, or Safari 7+. Please upgrade your web browser or use one of the recommended versions.
This is my version info:
Version: 39.0.2248.0 - Opera is up to date
Update stream: developer
System: Windows 10 64-bit
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2739.0 Safari/537.36 OPR/39.0.2248.0 (Edition developer)
Why is this happening?