Under previous K Desktop Environment versions, Konqueror had served both as the default file manager and web browser. However, for many years users have been critical of Konqueror as being too complex for simple file navigation. As a response, the two functions were divided into two separate applications. Under KDE SC 4, Dolphin was streamlined for browsing files, while sharing as much code as possible with Konqueror. Konqueror continues to be developed primarily as a web browser.
In 2014 work started on porting Dolphin to KDE Frameworks 5. This is now complete and a Frameworks 5-based version was released as part of KDE Applications 15.08 in August 2015.
As development of the KDE SC 4 version was underway, the K Desktop Environment 3 version of Dolphin was discontinued. However, the program continues to be unofficially available for K Desktop Environment 3 under the slightly modified name of “D3lphin”. D3lphin contains many bugfixes and a new sidebar, but is no longer maintained.