Differences between SMF 2.0 and SMF 1.1

Core Features
All the Core Features can now be enabled/disabled from a common page. This is a list of new core features available with SMF 2.0:
 * Advanced Profile Fields
 * Post Moderation
 * Moderation, Administration, and User Logs
 * Paid Subscriptions
 * Warning System
 * Search Engine Tracking

Theme Management

 * You can now edit every template file on any theme including the defaul. (SMF 1.1 only allowed you to edit non-default themes files)
 * change forum width from the admin panel

Permission System Changes

 * Permission system is now based on profiles.

Personal Messages

 * Rules can be created to automatically sort incoming personal messages
 * Display Personal messages all at once, one at a time and as a conversation

Package manager

 * Package manager tries to apply changes to non-default themes too.
 * Emulate version for mod install/uninstall.
 * Install packages from a URL

Administrative/Server management

 * Scheduled tasks
 * Mail queue
 * Load balancing
 * Multiple attachments directories
 * Languages installer
 * Edit meta description from admin panel
 * A default php-based caching
 * Ability to turn on/off signatures in admin panel

Registration and Anti spam

 * OpenID
 * Verification questions
 * Password strength

Members and topics management

 * Reattribute User Posts
 * Remove Inactive Members
 * (maintenance) move all topics from a board to another
 * Three more group types: Protected, Requestable and Free
 * Moderation center
 * Birthday emails
 * WYSIWYG editor
 * Consolidation and improvement of Buddy and Ignore lists (and related notification settings)

The New Default Theme "Curve"
Packaged since RC3 of the 2.0 series, is a new default theme called Curve. The original default theme, called Core, is still included with SMF 2.0.

Code related changes

 * support for PostgreSQL and SQLite
 * Integration Hooks
 * Better separation of theme and code (e.g. menu "definition" is now in Source.php so that is no more necessary to change each theme one by one to add or remove a menu entry)
 * $smcFunc
 * See also: Mod authors: Changes in SMF 2.0