Yesterday we got the release of Xojo 2015r3. The people with Xojo Pro on the beta program used it for a while already. We compiled various projects for 64-bit and tried what works and what not. In general I would consider the 64-bit support being a beta. Yes, it works, but not always. There are a couple of issues and without the debugger it is not really fun.
We got a new compiler based on the LLVM project. And a new runtime with 64-bit and Linux ARM support. Our plugins are compiled for both targets in version 15.4pr3. Plugin download.
Please try the plugins and report any problems you see. And when you see a bug, it could be the LLVM compiler optimizing more away than needed, the Xojo runtime could have a bug and our plugin could have a bug. Or the code you wrote may behave different in 64-bit.
With 15.4 plugins we will support 64-bit. Current prerelease 3 is on a good way, but still we find issues and old code to update. So prerelease 4 will fix a couple more things we discovered. Please try plugin and report any issue as soon as possible.
For a review on what is new in Xojo 2015r3, please check Bob Keeney's blog, the Xojo blog and the next issue of the Xojo Developer Magazine