The tarballs for the release of LyX 2.1.5 can be found here: ftp://ftp.lyx.org/pub/lyx/devel/lyx-2.1/2.1.5/ Please prepare binaries.
I will be at a conference all week. I'll have email access, of course, but I won't be at the right IP address for uploading files to ftp.lyx.org. So I will plan to do the actual release next weekend. Richard