Differences between SMF 2.1 and SMF 2.0

General and security

 * Handling of attachments (based on mod [Improved Attachment Error Handling]
 * Tokens (security)
 * End of admin and moderator sessions (security)
 * IPv6 support
 * Smart-emulation (the package manager is now able to propose a SMF version to emulate in order to install a mod)
 * New tags for packages: (tag for inserting mod credits in to the credits page), (tag to basic mod dependency), (tag to add / remove hooks)
 * Detection of mobile devices
 * Previews of several things are now available (Personal messages (now AJAX), news and newsletters, warning template and warnings, signature)

Hooks

 * Many more hooks (will follow a list of the most important)