There are many improvements and new features in Privoxy 3.0.4 :
Mulitiple filter files can now be specifed in config. This allows for locally defined filters that can be maintained separately from the filters as supplied by the developers.
There are a number of new actions:
In addition, fast-redirects has been significantly improved with enhanced syntax.
And hide-referrer has a new option, conditional block.
MS-Windows versions can now be installed and started as a Windows service.
config has two new options: enable-remote-http-toggle, and forwarded-connect-retries.
And there is improved handling of the user-manual option, for placing documentation and help files on the local system.
Actions files problems and suggestions are now being directed to: http://sourceforge.net/tracker/?group_id=11118&atid=460288. Please use this to report such configuration related problems as missed ads, sites that don't function properly due to one action or another, innocent images being blocked, etc.
In addition, there are various bug fixes and significant enhancements, including error pages should no longer be cached if the problem is fixed, better DNS error handling, and various logging improvements.
A quick list of things to be aware of before upgrading from earlier versions of Privoxy:
Some installers may remove earlier versions completely, including configuration files. Save any important configuration files!
On the other hand, some installers may not overwrite any existing configuration files, thinking you will want to do that. You may want to manually check your saved files against the newer versions to see if the improvements have merit, or whether there are new options that you may want to consider. There are a number of new features, but most won't be available unless these features are incorporated into your configuration somehow.
See the full documentation on fast-redirects which has changed syntax, and may require adjustments to local configs.
The jarfile, cookie logger, is off by default now.
What constitutes a "default" configuration has changed, and you may want to review which actions are "on" by default. This is primarily a matter of emphasis, but some features you may have been used to, may now be "off" by default.
Some installers may not automatically start Privoxy after installation.