Differences Between 3.x and 5.x

Here are some of the major changes between Siteframe 3.x and Beaumont (5.x):

Siteframe 3.x had a number of document types: Article, Uploaded File, Image, Event, Poll, etc. Beaumont has a single Page object, with optional file attachments. The structure is much easier to understand and use in Beaumont.
Beaumont does not support Poll or Event data because of insufficient demand.
Siteframe 3.x used a proprietary template engine; Beaumont uses the industry-standard Smarty template engine. Smarty is vastly more efficient and flexible than the older version.
Beaumont allows users to invite new users to join; this streamlines the registration and sign on process.
Beaumont has security tests to prevent automated scripts from creating accounts.
Siteframe 3.x produced image thumbnails in a fixed set of sizes; Beaumont supports on-demand creation of thumbnails in any desired size, giving more flexibility to the page designer.
Siteframe 3.x stored templates in the database, which required online editing; Beaumont stores templates in files, which means that you can use any editor or tool to create and maintain them.

There is a facility in 5.x to assist with migrating data from a 3.x website; however, because of the substantial differences, especially in how templates are handled. it is not really possible to simply upgrade a site from version 3 to version 5.

General Info

Differences Between 3.x and 5.x