This is the short list of changes since Akeeba Backup 3.0.1. Items applicable only to the Professional (subscription) version are marked as "PRO".
New features
PRO RackSpace CloudFiles support
PRO Microsoft Azure BLOB Storage support
PRO CLI backup now displays timestamp of last tick and memory usage information
PRO JPS support: AES-128 encrypted archives loosely based on the JPA format
PRO Native CRON Script now allows you to override configuration variables, e.g. supply usernames and passwords to cloud storage services.
PRO JPS Integrated restoration support
Akeeba Backup Lazy Scheduling plugin so that you never have to deal with CRON again
ABI: New "Use REPLACE instead of INSERT" option to work around "Duplicate entry" errors on some environments
ABI: Now allows enforcing UTF-8 collation for tables, no matter what the database's collation is
Post-processing right after part generation, allowing for cloud backups under tight disk space conditions
JSON front-end API with support for encrypted communications (encryption only in Pro)
Back-end backup "Alternate AJAX" mode using hidden IFRAMEs (compatibility mode)
Caching of obsolete status of backup records leads to faster "Administer Backup Files" page
Localisable installation interface
Improved backup engine, allows for simultaneous backups from different origins (e.g. one front-end and one back-end backup running at the same time).
Incremental file-only backup, based on the last modified time stamp of the files
The directory in post-processing engines now supports the same variables as the archive name ([DATE],[TIME],[HOST],[RANDOM])
Added notice on Configuration page about accessing the file, directory, database, etc filters
The active profile is displayed throughout the component's filter pages
Backup - and restoration - of date and time stamps in JPA files
Backup description and comment are automatically stored in installation/README.html for future reference
Now allows use of "variables" ([DATE],[TIME],[HOST],[RANDOM]) in the backup description and comment
ACL support for Joomla! 1.6, allows for discrete backup, download, configuration, managment and administrative privileges
Changes
Live Update is now using HTTPS to encrypt your login credentials
The "Backup Now" button pulsates to be more evident that you have to actually click on it...
Improved (more verbose) error reporting on cloud/remote storage failure
Added a logo to all pages and improved visual consistency
Removed menu links from the back-end menus. This eliminates backup failures which would have been avoided if the user had visited the Control Panel page to "reset" the backup engine's state.
Bug fixes
Backup Now would not work if the WYSIWYG editor crashed
magic_quotes_gpc would cause Javascript errors to be thrown and potentially break the Backup Now button in some languages
ABI: Verifying the FTP directory didn't work
ABI: Would erroneously replace akb_ in the data with the table prefix, breaking Community Builder
ABI: Warnings thrown from installation/includes/utils.php (cosmetic)
ABI: In theory you could use an automation file named jpi4automation.ini, but it was mispelled in the code and never worked
ABI: CRITICAL! Changing the SA password would make logging in to the site impossible
Using SSL for cloud uploads on Windows would cause an error due to outdated CA bundled with cURL on that platform
Calls to JError in the context of the native CRON script would cause a PHP fatal error
ABI: The final step of the auto mode was broken
ABI: Temporary and log directory paths where garbled on Windows hosts with magic_quotes_gpc turned on
ABI: When a database is created, the default collation wasn't set. Now forced to utf8_general_ci.
Post-proc FTP: Forcibly adds a leading forward slash to the initial directory to avoid connection problems if you forget to put it there
Large archive downloads (usu. over 30Mb) through the browser would fail on many hosts, returning Error 500, Error 406 or "File not found" messages. A better workaround is applied. Please report your results.
DROP statements would not be produced in SQL-only backup types
Archiving files with non-ASCII names on systems with mb_string function overload would fail
The active filter icon background was too faint and didn't display very well on laptop screens
There wasn't enough room for the "Backup Now" translation on many languages; button enlarged
The buttons in the Database Table Exclusion page were using the wrong mouse cursor
The layout would break when using JoomlaBamboo's Crisp admin template
Split ZIP archives could have corrupt Central Directory headers
Typo in tempfiles.php would throw a warning
All non-back-end backup modes were broken after SVN183 due to backup tag handling and not laoding the profile configuration properly
Infinite loop in front-end backup
The ZIP archiver would throw a warning due to a missing class field
Trying to save the Configuration on some servers results to redirection to the admin index page
Some servers throw an "Invalid AJAX data" message upon trying to use pretty much anything in Akeeba Backup's interface, including Backup Now itself
Live Update was using Joomla!'s downloader, based on fopen() URL wrappers and failed upgrading on hosts where cURL is available but URL wrappers are not
A stale storage file could cause the temporary and output directories to be reported as unwritable
MyBlog's cache directory (components/libraries/cmslib/cache) can cause backup errors. It's now automatically excluded.
CRITICAL Misleading button labels in integrated restoration (Pro release) could lead to a user erasing his entire site.
Permissions for virtual (installer) files in JPA and JPS archives were set to 0777 when they should have been 0755 for security reasons if and only if someone used the permissions restoration feature of Kickstart 3.1.1 or later