This is another release of the 1.5.x development branch. That means it may include a bigger amount of bugs than the 1.4.x branch and each version is not compatible with another one from the 1.4.x and 1.5.x branch since we do change quite a lot between the releases. Keep in mind, it might be a lot more buggy than the 1.4.x branch so don't be disappointed if you get a crash every now and then. If you want to test the future of Wesnoth, you are free to check 1.5.6. It would be great if you reported any bug you find while playing 1.5.6 so that we have a chance to fix them before 1.6 is released.
The last release was some ages ago so thousands of changes were implemented. The most important one is probably the AI should be as smart again as it used to be. Beside this a new campaign, 'Legend of Wesmere' was added to mainline. There you can experience the history of Kalenz and face many dangers with the elvish troops. Another important note is that 'Under the Burning Suns' got a thorough cleanup including virtually hundreds of fixes finally making it enjoyable again.
Now is also the perfect time for translators to start working on the translations so that they can be complete in 1.6. The status of all the textdomains is listed on this wiki page. If you want to help translating Wesnoth into your language of choice, have a look at this page and contact the translations maintainer. The maintainer will tell you how you can help best.
Some other important things to mention:
The excessive AI cautiousness that afflicted the 1.5.5 release has been fixed.
Legend of Wesmere has been added to mainline.
There is a new tool for visually editing the journey tracks that appear on the story maps of many Wesnoth campaigns. It is called 'trackplacer', and you can read about it here: http://www.wesnoth.org/wiki/Authoring_tools
Many blocker bugs (yet not officially reported, *tsk*) related to the "update add-ons" dialog functionality have been fixed.
The music namespace has been reorganized a bit. UMC authors should know of the following name changes
- main_menu.ogg -> transience.ogg
- main_menu_new.ogg -> main_menu.ogg
- nr-sad.ogg -> sad.ogg
If you play campaigns utilizing the new gold carryover system (DiD, HttT, SoF, SotBE or TSG), you won't want to use the beginning-of-scenario saves because due to a bug, the carryover gold is not stored properly in them (so if you load from a beginning-of-scenario save, you'll end up with less gold than you should). Instead you should for example make manual turn 1 saves of each scenario and load those if you need to.
Of course there is also the full changelog listing (almost) all the changes since 1.5.5. A changelog with changes that might be visible to most users (and only includes these) is the players changelog.
http://downloads.sourceforge.net/wesnoth/wesnoth-1.5.6.tar.bz2?download (180.7 MB) md5sum
Here is the xDelta for the sources:
http://downloads.sourceforge.net/wesnoth/wesnoth-1.5.5.tar-wesnoth-1.5.6.tar.xdelta?download (1.5.5 to 1.5.6, 58.2 MB)
Check http://www.wesnoth.org/forum/viewtopic.php?t=7034 for info on using xdelta.
The Windows binary is available on the download page.
The MacOSX binary is available on the download page.
The OpenSolaris binary is not available yet. Once it is, you can find it on the download page.
All known packagers have been contacted. Information about where to get the respective binaries or how to get them work you get on the Linux binaries site for the Linux binaries. Download links for the other supported systems will be listed at the downloads page once the binaries are available.
As a fallback you can also get the sources from http://files.wesnoth.org/ - you should first try to get files through SourceForge to help us save bandwidth. Please get the files from sourceforge.net if possible.
The multiplayer server for 1.5.6 is already up and running. This server can only be used to play with 1.5.6. If you do encounter problems, please report them.
If you find any bugs don't hesitate to report them, but please read the instructions on how to post bugs first. Instructions for bug reporting can be found at http://www.wesnoth.org/wiki/ReportingBugs.
PS: Within the next seven days anyone asking when the binary for xyz will be ready will be banned and the post will be deleted. Such questions just distract the developers and packagers and don't do any good, so better not ask them...
Bugreports in the forums tend to get forgotten. You will get better results by following the guidelines and report them in the bugtracker.