1.5.15 release. http://aws.amazon.com/releasenotes/5261285417896036
Update README.md
1.5.16 release. http://aws.amazon.com/releasenotes/8545761433555407
1.5.16.1 release. http://aws.amazon.com/releasenotes/8545761433555407
1.5.17 release. http://aws.amazon.com/releasenotes/4784062790863697
1.5.17.1 release. http://aws.amazon.com/releasenotes/PHP/4784062790863697
1.6.0 release. http://aws.amazon.com/releasenotes/2238950844718536
stashing