question

Hello, We recently switched from AWS Signature V2 to V4 for uploading files via the browser to a S3 bucket, and verified everything was working successfully. Sometime around Feb 29th our automated test suite started failing, claiming that: [b]The request signature we calculated does not match the signature you provided. Check your key and signing method[/b] Our implementation hadn't changed, so it was strange that this started to happen in all of our test/production environments. We determined that the timestamp we used to calculate the signature was ISO8601 format rather than the YYYYMMDD format. We also determined that the timestamp portion of the path in the x-amz-credential header was also ISO8601. We fixed those two issues and were once again able to upload files using V4. What we can't explain is how this was working for the last two weeks. I tried to find release notes related to some kind of change to the V4 verification service to see if there were bug fixes pushed recently, but I couldn't find anything. Does anyone know if the service was changed recently?