In a client-server computer system, an active cache is utilized by a client-based project management application program to share server-based project files with an offline client, so that the project files may be updated by modifications made offline. A project file is saved from the active cache for sharing with the offline client. The shared project file is sent to the offline client for editing. After editing, a modified project file is received from the offline client and saved to the active cache. The active cache initiates an update of the server-based project file with the project file which was modified offline.