Please be sure to read the follow up post concerning a specific issue with Harmony, Mountain Lion and Accordance.
What is OS X Mountain Lion?
A few weeks ago, Apple announced that OS X Mountain Lion would be available in July 2012. It is the new release of OS X, the operating system for Apple's Mac computers, and replaces OS X Lion. It's version number is 10.8.
Does Harmony run on OS X Mountain Lion?
We are pleased to announce that Harmony 2.5.3 is fully supported on Macs running OS X Mountain Lion.
What do I need to be aware of?
Versions of Harmony prior to 2.5.1 will have problems on OS X Mountain Lion. Firstly, Harmony 2.5 and earlier will not run on OS X Mountain Lion with default Gatekeeper settings. So if you can, upgrade Harmony before upgrading to OS X Mountain Lion. Learn more about Gatekeeper. Also, SongSelect Import does not work in Harmony 2.5 and earlier on OS X Mountain Lion.
Wait, do I need Harmony 2.5.1 or 2.5.3 for OS X Mountain Lion support?
Short answer: 2.5.3
Despite the fact that there are fixes related to OS X Mountain Lion starting with Harmony 2.5.1, please upgrade to Harmony 2.5.3 which contains additional fixes and support for the new SongSelect.
I purchased Harmony from the Mac App Store. I don't see the 2.5.3 update.
The 2.5.3 update has been submitted to the Mac App Store and is awaiting approval. All Mac App Store downloads run under the default Gatekeeper settings.
UPDATE Jul 31, 2012: The 2.5.3 update is now available in the Mac App Store.
Does Harmony 2.5.3 run on Mac OS X Snow Leopard (10.6) or Lion (10.7)?
Yes. All 2.x versions of Harmony are designed to run and supported on Mac OS X Snow Leopard. 2.1.1 and later are supported on Mac OS X Lion.
What about Accordance?
UPDATE Aug 23, 2012: The Mac App Store edition of Harmony cannot access Accordance on OS X Mountain Lion 10.8.0, 10.8.1 or 10.8.2. We have a separate post regarding this issue.
Note of caution
As with all major computer upgrades, we advise you to test in your environment before going live.
If you encounter bugs or other unexpected behavior, please log a problem in our support system.