For access to stored objects, Perst implements specialized collection classes including:   To facilitate changes to an existing database design (database schema), Perst implements “lazy” database schema evolution. When an object instance is loaded from the database, its class descriptor is compared with the format of the class in the application. If they are not identical, and the object is to be changed, then the object is converted and stored in the new format. With an “eager” schema evolution format changes would sweep through the database all at once. ProScout is a demo midlet for using Perst Lite in the Java ME environment. The demonstration is of a discrete note-taking facility for a sports recruiter. Originally implemented for the Blackberry, it has also been deployed on the Nokia S60. McObject provides a demo app of a CRM system using Perst for .NET, including a fully text-searchable contact database that runs in the desktop browser in Silverlight. Andy Wigley, of appamundi, ported this demo app to Windows Phone and described the project in a series of blog postings. Users can redistribute and/or modify Perst under the terms of the GNU General Public License (version 2 or later) as published by the Free Software Foundation. For individuals or organizations that cannot or do not wish to comply with the GPL, a commercial license is available from McObject.