I'm working on a Sitecore 8.1 (rev. 160302) build running our custom code on .NET 4.5. As far as I know using the out of the box Security provider there are no ways to update username programatically as it's a read only property. I know this is possible using ASP.NET Identity framework but as far as I can tell this build version does not use the identity framework.
Are there any ways of updating the username for this version?