Much of this information will be familiar to those who were following the development process over at the XF2 Demo Forums, but this is something of a ‘greatest hits’ list of some of the important changes and improvements to XenForo since the 1.x generation.
Greatly-enhanced mobile-friendly style
The new XenForo 2 style is the first thing you will notice in XF2. The entire style has been redesigned with a fresh new appearance, but also with mobile browsing at the forefront of the design. When the viewport shrinks, on-page content shrinks, shifts and reorganises itself automatically to optimise the browsing experience for small displays.
A sticky header automatically activates when the window is scrolled, allowing the most important navigation controls to remain available at all times.
Emoji support*
All textual content in XenForo 2 now supports emoji, from message text to forum titles.
Retina avatar and smilie support
Avatars and smilies now support high-DPI imagery, allowing for a crisp, high resolution display to match the text on displays that support 2x resolution graphics, such as Apple's retina displays.
Navigation manager
Both the public-facing systems and the admin control panel now have completely customizable navigation systems, allowing the content of the navigation bars and side-navigation blocks to be entirely controlled by the site administrator without any need to resort to template modification.
Widgets
Widgets are small blocks of content that can perform a variety of tasks, such as displaying a list of members online, or latest posts etc. Widgets can be placed into various pages within the public-facing side of XenForo using a simple interface, allowing you to build rich content-discovery systems into almost any area of the public forums.
Enhanced message editing
Rather than opening an overlay, editing messages is now done entirely in-place, with the content of messages replaced by a full-fledged message editor that allows the complete range of editing and posting actions, including attachment management.
Alerts in favicon
When new alerts or unread conversation messages are available, the site icon (shown in the browser title bar) will have a badge added to it, showing that there are items waiting to be viewed.
Custom thread fields
An extension of the custom user field system, threads can now have their own custom fields, with all the functionality previously available for user fields. Thread fields can be displayed before or after message content, and can be made editable and optionally required before a thread is posted.
Member tooltip
XF1's member card has been replaced with a new member tooltip, which appears on the first click on a member's name. A further click will load the member's full profile page.
CSS transitions replace Javascript animations
Leveraging modern browser capabilities, almost all of the animations seen in XF2 make use of CSS transitions rather than Javascript animations, resulting in smoother, less processor-intensive transitions between states.
Customisable member stats
The old member list page has now been replaced by an all-new, customizable member statistics system. Individual statistics (such as members with the most posts, most recently-registered members etc.) can be built using an interface in the admin control panel, and are then displayed as an expandable block on the members page.
Generic payment framework
XenForo 2 has a new payment system that is open for development, meaning that add-on developers can quickly and easily build payment gateways for providers that are not part of the core system. Using this system, XF2 ships with a number of ready-made payment options that are easy to integrate with various system enhancements that administrators may define.
Attachments shown in previews
Content previews, such as those seen when hovering a thread title on the thread list page, now include attachments for a more complete and integrated preview experience.
Enhanced code block syntax highlighting
The [CODE] block system has been greatly enhanced to display syntax highlighting for a much wider range of programming and scripting languages through the use of [CODE=language] tags.
What’s New and Find Threads
To aid in content discovery, XF2 includes a brand new 'What's new' system, which can fetch new content from all sources across the system, including threads and posts, profile posts, media items and resources. The architecture of the system is fully extensible, so add-on developers can hook into What's new in order to add their own content types to the results.
Additionally, a new Find threads system provides quick links to unanswered threads (with no replies), threads you have started, and threads in which you have posted.
New media embedding features
The BB Code Media system has been significantly enhanced, and now supports embedding Facebook posts, Tweets, Instagram photos, Reddit posts and comments, Spotify and Soundcloud tracks, albums and playlists and a whole host of others.
The integration of oEmbed support allows almost any media to be embedded simply by pasting a link to the media within a message.
Quick thread
Quick Thread is a brand new system for XF2. Above the list of threads on a forum page you will find a title entry box. Focusing this box and starting to type a thread title will load a quick message editor, in which you can post the content for the first post of your new thread. Hitting the save button will then post the thread, leaving you on the forum page rather than redirecting you to the thread page. This makes the process of creating a new simple thread extremely quick and easy.
Thread prompts
In conjunction with Quick thread, Thread prompts allow the title input box to display a configurable prompt, giving members a hint as to what kind of content they should be posting in any given forum. Multiple prompts may be defined and assigned to forums, and an applicable prompt will be selected at random to be displayed to the user when the page loads.
Keyboard shortcut system and enhanced keyboard navigation
XenForo 2 includes an easy method to assign keyboard shortcuts to commonly-used controls, such as searching and opening the alerts list. These shortcuts are defined with simple template edits, and allow for very rapid navigation with a keyboard.
Additionally, the system can determine whether the user is currently using touch, mouse or keyboard navigation at any given time, and will highlight the currently-selected link or control appropriately when keyboard navigation is enabled, while hiding the selection when using touch or mouse methods.
New custom field options
Custom fields have had an overhaul for XF2, and now include a star-rating type, along with various validation options including dates and numbers. These enhancements apply to all custom field types, including user fields and thread fields, and are automatically available for any custom field types defined by add-ons.
HTML 5 input types
To make data input on mobile devices more friendly, we make more extensive use of HTML 5 input types, allowing specialised keyboards to be displayed in place of the standard character keyboard. For example, when an input requires only a number, a telephone-style keyboard is displayed.
Developer / designer mode
While XF1's WebDAV system has been retired, XF2 has a whole new range of enhancements for rapid style development, including a system whereby templates can be edited directly in the file system using any editor of your choice. In designer mode, when the system detects a modified template, it will be compiled ready for the next page view that requires that template.
CLI tools
For add-on developers and large board administrators, XF2 now includes a comprehensive suite of command line tools, allowing operations such as upgrades and add-on manipulation to be done from the terminal rather than having to operate through a web interface. This can be of huge benefit for long operations, such as recompiling all templates or upgrading a large site.
* Note that while emoji support is enabled by default on new installations, sites that have been upgraded from XenForo 1.x will require a script to be run in order to convert all text to a new emoji-supporting character set (utf8mb4). This can be a relatively long process, and administrators should perform test-runs to determine how long the process will take for their final upgrade.
Greatly-enhanced mobile-friendly style
The new XenForo 2 style is the first thing you will notice in XF2. The entire style has been redesigned with a fresh new appearance, but also with mobile browsing at the forefront of the design. When the viewport shrinks, on-page content shrinks, shifts and reorganises itself automatically to optimise the browsing experience for small displays.
A sticky header automatically activates when the window is scrolled, allowing the most important navigation controls to remain available at all times.
Emoji support*
All textual content in XenForo 2 now supports emoji, from message text to forum titles.
Retina avatar and smilie support
Avatars and smilies now support high-DPI imagery, allowing for a crisp, high resolution display to match the text on displays that support 2x resolution graphics, such as Apple's retina displays.
Navigation manager
Both the public-facing systems and the admin control panel now have completely customizable navigation systems, allowing the content of the navigation bars and side-navigation blocks to be entirely controlled by the site administrator without any need to resort to template modification.
Widgets
Widgets are small blocks of content that can perform a variety of tasks, such as displaying a list of members online, or latest posts etc. Widgets can be placed into various pages within the public-facing side of XenForo using a simple interface, allowing you to build rich content-discovery systems into almost any area of the public forums.
Enhanced message editing
Rather than opening an overlay, editing messages is now done entirely in-place, with the content of messages replaced by a full-fledged message editor that allows the complete range of editing and posting actions, including attachment management.
Alerts in favicon
When new alerts or unread conversation messages are available, the site icon (shown in the browser title bar) will have a badge added to it, showing that there are items waiting to be viewed.
Custom thread fields
An extension of the custom user field system, threads can now have their own custom fields, with all the functionality previously available for user fields. Thread fields can be displayed before or after message content, and can be made editable and optionally required before a thread is posted.
Member tooltip
XF1's member card has been replaced with a new member tooltip, which appears on the first click on a member's name. A further click will load the member's full profile page.
CSS transitions replace Javascript animations
Leveraging modern browser capabilities, almost all of the animations seen in XF2 make use of CSS transitions rather than Javascript animations, resulting in smoother, less processor-intensive transitions between states.
Customisable member stats
The old member list page has now been replaced by an all-new, customizable member statistics system. Individual statistics (such as members with the most posts, most recently-registered members etc.) can be built using an interface in the admin control panel, and are then displayed as an expandable block on the members page.
Generic payment framework
XenForo 2 has a new payment system that is open for development, meaning that add-on developers can quickly and easily build payment gateways for providers that are not part of the core system. Using this system, XF2 ships with a number of ready-made payment options that are easy to integrate with various system enhancements that administrators may define.
Attachments shown in previews
Content previews, such as those seen when hovering a thread title on the thread list page, now include attachments for a more complete and integrated preview experience.
Enhanced code block syntax highlighting
The [CODE] block system has been greatly enhanced to display syntax highlighting for a much wider range of programming and scripting languages through the use of [CODE=language] tags.
What’s New and Find Threads
To aid in content discovery, XF2 includes a brand new 'What's new' system, which can fetch new content from all sources across the system, including threads and posts, profile posts, media items and resources. The architecture of the system is fully extensible, so add-on developers can hook into What's new in order to add their own content types to the results.
Additionally, a new Find threads system provides quick links to unanswered threads (with no replies), threads you have started, and threads in which you have posted.
New media embedding features
The BB Code Media system has been significantly enhanced, and now supports embedding Facebook posts, Tweets, Instagram photos, Reddit posts and comments, Spotify and Soundcloud tracks, albums and playlists and a whole host of others.
The integration of oEmbed support allows almost any media to be embedded simply by pasting a link to the media within a message.
Quick thread
Quick Thread is a brand new system for XF2. Above the list of threads on a forum page you will find a title entry box. Focusing this box and starting to type a thread title will load a quick message editor, in which you can post the content for the first post of your new thread. Hitting the save button will then post the thread, leaving you on the forum page rather than redirecting you to the thread page. This makes the process of creating a new simple thread extremely quick and easy.
Thread prompts
In conjunction with Quick thread, Thread prompts allow the title input box to display a configurable prompt, giving members a hint as to what kind of content they should be posting in any given forum. Multiple prompts may be defined and assigned to forums, and an applicable prompt will be selected at random to be displayed to the user when the page loads.
Keyboard shortcut system and enhanced keyboard navigation
XenForo 2 includes an easy method to assign keyboard shortcuts to commonly-used controls, such as searching and opening the alerts list. These shortcuts are defined with simple template edits, and allow for very rapid navigation with a keyboard.
Additionally, the system can determine whether the user is currently using touch, mouse or keyboard navigation at any given time, and will highlight the currently-selected link or control appropriately when keyboard navigation is enabled, while hiding the selection when using touch or mouse methods.
New custom field options
Custom fields have had an overhaul for XF2, and now include a star-rating type, along with various validation options including dates and numbers. These enhancements apply to all custom field types, including user fields and thread fields, and are automatically available for any custom field types defined by add-ons.
HTML 5 input types
To make data input on mobile devices more friendly, we make more extensive use of HTML 5 input types, allowing specialised keyboards to be displayed in place of the standard character keyboard. For example, when an input requires only a number, a telephone-style keyboard is displayed.
Developer / designer mode
While XF1's WebDAV system has been retired, XF2 has a whole new range of enhancements for rapid style development, including a system whereby templates can be edited directly in the file system using any editor of your choice. In designer mode, when the system detects a modified template, it will be compiled ready for the next page view that requires that template.
CLI tools
For add-on developers and large board administrators, XF2 now includes a comprehensive suite of command line tools, allowing operations such as upgrades and add-on manipulation to be done from the terminal rather than having to operate through a web interface. This can be of huge benefit for long operations, such as recompiling all templates or upgrading a large site.
* Note that while emoji support is enabled by default on new installations, sites that have been upgraded from XenForo 1.x will require a script to be run in order to convert all text to a new emoji-supporting character set (utf8mb4). This can be a relatively long process, and administrators should perform test-runs to determine how long the process will take for their final upgrade.
, no outdated templates on 1.5.16 and 2.0 stable, we're off to a good start.
) and from all you other developers out there 
) ago and everyone, no matter how big or small their part may be, does an outstanding job behind the scenes and we'll all continue to do our bit long into the future to the best of our ability.
