AWS SDK for .NET Documentation
LastModified Property
AmazonAmazon.S3.ModelS3ObjectLastModified Did this page help you?   Yes   No    Tell us about it...
The date and time the object was last modified.
Remarks
The date retrieved from S3 is in ISO8601 format. A GMT formatted date is passed back to the user.
Declaration Syntax
C#
public string LastModified { get; set; }

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)