- Accurate progress for restore process.
- Restore process can be canceled without delay.
- Can backup and restore programs bigger than 4GB.
- Several interface translations are updated.
- Main form can be resized to a smaller size.
- Extra safety checks in the program analyzer.

Several fixes when importing email from Microsoft Outlook
Mozilla platform changes
Added support for the latest draft version of WebSockets with a prefixed API
Added support for EventSource / server-sent events
Added support for window.matchMedia
Added a plugins check link to the Plugins pane of the Add-ons Manager
Added support for the <progress> element, touch events and Server-Sent Events

The changes page lists a more detailed overview of new features and fixes relative to our last stable release, SeaMonkey 2.2. Relevant security fixes are listed on Security Advisories for Firefox (Firefox 6).

Downloading
The SeaMonkey project provides official versions of SeaMonkey 2.3 for Windows, Linux, and Mac OS X in US English and experimental language packs for a small variety of other languages. Community volunteers are also contributing builds for other platforms. You can download SeaMonkey 2.3 here.
System Requirements, Installation and Uninstallation
Before installing, make sure your computer meets the system requirements. SeaMonkey 2.3 will offer to migrate your data from SeaMonkey 1.x or Mozilla 1.x at the first start after installation. You can find more details about installation, profile data and uninstallation in our install and uninstall document.
Extensions and Themes
Extensions installed under SeaMonkey 1.x are not migrated to SeaMonkey 2, and may not be compatible for reinstalling in this version due to major changes in our architecture. Please report any issues to the maintainer of the extension. Extensions and Themes for SeaMonkey 2.3 can be installed from the SeaMonkey Add-Ons website or the "Get Add-Ons" section in the Add-ons Manager.
Known Issues
This list covers some of the known problems with SeaMonkey 2.3. Please read this before reporting any new bugs.
Data loss warning: If you use a profile with this or any later version and then try to go back to SeaMonkey 2.0, SeaMonkey will rename your history file to places.sqlite.corrupt and create a new places.sqlite file, effectively resetting your browsing history. This is because the internal format changed and the upgrade process only works in one direction.
If you are using SeaMonkey with one of the following locales, Help will be broken. We hope to fix this for the next release. The locales are: en-GB (British English), es-AR (Argentine Spanish).
After creating a news account through clicking a news URL, the MailNews account wizard may be broken (the account type will always be News). To work around the problem, set the mail.server.serverX.valid pref (where X is the internal number of the corresponding news account) to true in about:config, or delete the invalid news account (bug 521861).
Select Element by Click doesn't flash the element in DOM Inspector on Windows (bug 594299).
Some parts of Sync setup and preferences (e.g. Change Password and My Sync Key) are not working anymore (bug 679773). This will be fixed for the next release.
To use a Sync account with multiple devices you need to make sure all of them use the latest version of Sync (e.g. SeaMonkey 2.1 in combination with Firefox 4, desktop and mobile) (bug 615950).
The option "When opening a bookmark group" / "Replace existing tabs" under Preferences / Tabbed Browsing does not have an effect anymore (bug 664101).
Bookmark This Group of Tabs is greyed out after restart with session restore (bug 677539). This will be fixed for the next release.
Some icons in the Add-ons Manager are missing with the Modern theme (bug 666873). This will be fixed for the next release.
Lightning options cannot be opened from the Add-ons Manager. Instead, Lightning preferences can be accessed from Preferences/Lightning (bug 636104).
Lightning keyboard shortcuts for accessing the calendar tab from within the MailNews window or from the main menu (Ctrl+Shift+C/D) do not work. (bug 514512).
After installing Firebug 1.7.x and restarting the application, the Navigation Toolbar may be broken (bug 658444), and opening Firebug in its own window will break it for the rest of the session. Both issues have been fixed in Firebug 1.8.0a3.
If you try to start SeaMonkey using a locked profile, it will crash (see bug 573369).
Mac:
When hardware acceleration is off, background colors in the UI (toolbar, status bar etc.) might not update correctly when you switch focus from/to a window. Users running Macs with certain older hardware (e.g. Intel GMA 950) will experience this even if they haven't turned off hardware acceleration in Preferences (Appearance/Content) (bug 626096).
Linux:
The video control buttons may not work when viewing QuickTime videos with libtotem (bug 625036).
Troubleshooting
Some questions are asked more frequently than others. Have a look at the SeaMonkey 2.1 FAQ. Maybe your particular problem has already been solved.
Some anti-virus software keeps detecting our installers as containing a "Trojan" or "Downloader". This is a false positive and is some wrong detection mechanism in the anti-virus software. The code in question is actually from 7-Zip and decompresses the installer so that its contents can run and install SeaMonkey. That technology is widely used and probably can be used to compress bad as well as good software, but the 7-Zip code itself is perfectly safe. Mozilla scans all our files routinely when putting them on the FTP server and we assure you that our installers are as clean as the official Firefox downloads that are scanned by the same mechanisms.
Poorly designed or incompatible extensions can cause problems with SeaMonkey, including make it crash, slow down page display, etc. If you encounter strange problems relating to parts of SeaMonkey no longer working, the browser not starting, windows with strange or distorted appearance, degraded performance, etc, you may be suffering from Extension or Theme trouble. Restart SeaMonkey in Safe Mode. On Windows, start using the "Safe Mode" shortcut created in your Start menu or by running seamonkey.exe -safe-mode. On Linux, start with ./seamonkey -safe-mode and on Mac OS X, run:
cd /Applications/SeaMonkey.app/Contents/MacOS/
./seamonkey-bin -safe-mode

When started in Safe Mode all extensions are disabled and the Default theme is used. Disable the Extension/Theme that is causing trouble and then start normally.
If you uninstall an extension that is installed with your user profile (i.e. you installed it from a Web page) and then wish to install it for all user profiles using the -install-global-extension command line flag, you must restart SeaMonkey once to cleanse the profile extensions datasource of traces of that extension before installing with the switch. If you do not do this you may end up with a jammed entry in the Extensions list and will be unable to install the extension globally.
If you encounter strange problems relating to bookmarks, downloads, window placement, toolbars, history, or other settings, it is recommended that you try creating a new profile and attempting to reproduce the problem before filing bugs. Create a new profile by running SeaMonkey with the -P command line argument, choose the "Manage Profiles" button and then choose "Create Profile...". Migrate your settings files (Bookmarks, Saved Passwords, etc) over one by one, checking each time to see if the problems resurface. If you do find a particular profile data file is causing a problem, file a bug and attach the file.

1. Fixed compatibility issue with old legacy FTP servers that only send without to indicate end of line on the command session.
2. Fixed flickering statusbar during redraw.