DropDMG 3.2.3, EagleFiler 1.6, and SpamSieve 2.9.10 have been tested with OS X 10.9. If you haven’t already updated to the latest versions of these applications, now is the time to do so. Any known issues are listed below, and this post will be updated should any new issues arise:

DropDMG

1. The Create OS X Install Disk help page describes how to create a Mavericks install disk using a spare hard drive, USB flash drive, or SD card. This makes it possible to re-install OS X or to install it on a different Mac without having to download it again from the Mac App Store.
2. Automator may crash when using DropDMG’s Create Disk Image/Archive action. We are looking into whether this is due to a bug in DropDMG or Mavericks and trying to find a workaround.

EagleFiler

1. The first time you open a library on Mavericks, EagleFiler will copy its tags to the system so that your files have the same tags in other applications as they have in EagleFiler. This will cause the files to be modified, which will trigger a one-time re-indexing (of files, not mail messages) in EagleFiler.
2. When you tag a file in EagleFiler, it applies the corresponding system-level tags in Mavericks. When you import a file into EagleFiler, it imports that file’s Mavericks tags. Currently, when a file is already in EagleFiler, if you change its tags using another application, the changes do not sync back to EagleFiler; this will be addressed in the next version of EagleFiler. Update (2013-12-19): EagleFiler 1.6.1 offers syncing with Finder tags.
3. EagleFiler’s “eftexttool” helper may crash when EagleFiler is indexing a Web archive. This is due to a bug in Mavericks (using NSURLRequestReturnCacheDataDontLoad). Update (2013-12-19): EagleFiler 1.6.1 works around this bug.
4. Due to a bug in Mavericks, the PDFs initially display partially scrolled down if you have both Zoom to Fit and Continuous Scroll enabled. Update (2013-12-19): EagleFiler 1.6.1 works around this bug.

SpamSieve

1. It is recommended that you update to SpamSieve 2.9.10 before installing Mavericks. If you’ve updated to Mavericks first, and you don’t see the SpamSieve commands in Apple Mail’s Message menu, be sure to choose Install Apple Mail Plug-In from the SpamSieve menu.
2. If you’ve been modifying SpamSieve’s Info.plist file to hide its Dock icon, be sure to follow the updated instructions for this when running on Mavericks.
3. In previous versions of OS X, if Apple Mail’s junk mail filter was enabled, it would color junk messages brown in the list; if it was disabled, messages marked as junk (by other filters) would appear with the normal color in the message list. In Mavericks, spam messages that were not processed by SpamSieve (e.g. those caught by your mail server’s junk filter and placed in the Junk mailbox) may be colored brown (as if Mail’s own filter were active). In all versions of Mac OS X, spam messages caught by SpamSieve are placed in the Spam mailbox, and the background is colored on a blue-to-yellow spamminess scale.
4. In previous versions of OS X, if Apple Mail’s junk mail filter was enabled, it would show a brown bar with a Not Junk button above the message; if it was disabled, Mail did not display the bar. In Mavericks, Mail now shows its junk mail interface for messages that are marked as junk/spam, even when Mail’s own junk mail filter is disabled. You should ignore this, i.e. always choose SpamSieve - Train as Good rather than clicking the Not Junk button.
5. Some customers have reported that installing Mavericks enabled Mail’s built-in junk mail filter, when it had previously been off. If you’re using SpamSieve with Apple Mail, go to the Junk Mail pane of Mail’s preferences and make sure that Enable junk mail filtering is unchecked.
6. We’ve also received reports that sometimes Mail’s junk filter colors messages in the inbox as junk (brown) even when Enable junk mail filtering is unchecked. It may help to:
   1. Go to Mail’s Junk Mail settings.
   2. Check Enable junk mail filtering.
   3. Select Perform custom actions.
   4. Click Reset… and then Reset.
   5. Click Advanced….
   6. Make sure there are two conditions. The first condition should be Message is not addressed to my full name. The second condition should be Message is addressed to my full name. Click OK.
   7. Uncheck Enable junk mail filtering.
7. With Mavericks, Apple Mail sometimes shows the special Junk mailbox at the top of the list, even when its own junk filter is off. The Junk mailbox holds spam messages caught by server-side junk filters. The spam messages caught by SpamSieve still go the the Spam mailbox, or whichever other mailbox you chose in the preferences.
8. Apple Mail in Mavericks is slower at moving messages via AppleScript. After training a message as spam, it may take a few seconds before it moves to the Spam mailbox. Please do not train a second batch of messages until the first batch has been completely processed. Update (2013-12-16): SpamSieve 2.9.1 includes a workaround that makes this faster. To enable the workaround, please see the AppleMailTrainSpamGUIScripting option in the Esoteric Preferences section of the manual.
9. This is not directly related to SpamSieve, but there are a variety of Apple Mail issues in Mavericks (follow-up) that you should be aware of (particularly if you use Gmail).
10. A bug in Mavericks (_NSDispatchData) may cause SpamSieve to crash when parsing an e-mail message. Update (2013-12-16): SpamSieve 2.9.12 works around this.