The wiki software that was initially used for Wikipedia was called UseModWiki and was written in Perl. With issues of scale starting to present themselves as Wikipedia grew, in the summer of 2001, Manske started work on a replacement for UseModWiki that would be database-backed and would contain "wikipedia-specific features". On 25 January 2002, Manske released the first version of a MySQL-based PHP wiki engine, called "Phase II". One innovation implemented by Manske in Phase II was the use of namespaces in order to separate different types of pages, such as the "Talk" or "User" namespace, which distinguished it from older wiki software which didn't have different namespaces. Phase II also introduced a number of other features which are still present, including file upload, watchlists, automatic signatures, and user contributions list. Manske's re-write also made it easier to integrate photographs in Wikipedia articles, and created a new user group: administrators, empowered to delete pages and block vandals.