AWS originally announced that Amazon S3 would stop supporting the old Signature Version 2 (SigV2) method starting June 24. Now it has changed its plan. Although new buckets no longer support SigV2, existing parts will continue to be available. Delete the parts related to SigV2 and use SigV4. For security purposes, all requests made by Amazon S3 API must be authorized by signature. Since Amazon S3 is an early service provided by AWS, it was released in 2006, so it uses SigV2 signature model. In 2012, AWS has also introduced SigV4, a more flexible signature method, which will be available in all regions after 2013.
www.ai.org.tw/map.asp