Indev Software released Mail Act-On 2.1 on Friday, an update that adds support for Snow Leopard and new features, too. Mail Act-On is a plugin for Apple's Mail.app that allows you to assign keystrokes to rule actions, allowing for increased efficiency and productivity. The new features include the introduction of Preferred Mailboxes, and the ability to apply rules in two new ways.

Preferred Mailboxes allow users to assign numerical designations to ten mailboxes that allow users to quickly assign e-mail to those ten mailboxes with two keystrokes (by default, F6 then a number key 0 - 9).

Another new features is allows users to configure their inbox, outbox, and individual Act-On Rules to activate other rules. You can do this to either the current or prior message. According to the company, when used creatively, you can sequence rules to build sophisticated AND/OR logic for rule criteria or apply secondary actions to subset of the messages caught by the first rule.

When using the previous message feature, you can create an outbox rule that automatically files the message you are replying to when you send the reply. Alternatively, you can create an inbox rule that will re-file your sent mail when you receive replies.

Other changes in this release:

Improvements

• Added Outbox rule criteria: Receiver is member of address book group.
• Added Act-On rule criteria: Message is in mailbox
• Added "Do not mark message as read" in Message Viewing options.
• Added contextual menu items to move/copy rules from one group to another.
• Improved Sparkle compatibility with other plugins that use sparkle (such as WideMail or Letterbox)
• Added Danish localization (Thanks to Sebastian Dyhr)

Bug Fixes

• Fixes registration issue in HUD windows
• Fixes preference window resizing when open and closing preference repeatedly.
• Fixes compatibility issue with MailTags 2.3 open beta (build 351)
• Fixes issue with setting number of recent projects/keywords for MailTags Extra

Indev Software also extended the trial version of the software from 21 days to 30 days. the update is free to registered users of version 2.x, and the full version is priced at US$24.95.