(i386 and amd64 packages only)
Apparently Gnucash is quite sensitive about certain conditions on the build platform, as I'm getting build failures when trying to backport it on my production 64-bit install of MX 15. (removing ~/.gnucash and guile's cache in ~ fixed them, though) I set up an OBS repository and populated it with some necessary updated build-depends from jessie-backports, then added modified 2.6.14 sources from the getdeb.net repo in order to try some experiments.
https://build.opensuse.org/project/show ... rt:Gnucash
Anyway, it turned out that a patch that Getdeb added caused a build failure in the self-testing part of the OBS build, so removing that allowed a successful build. The patch has no effect on a local build on my machines, though. You can add the repository by clicking on the gnucash package in the link above, and then on the "download package" link in the upper right and following directions as root or sudo. Note that if you have customized apt-pinnings, you may have to do some tricks to upgrade over the stock Gnucash, much like can be necessary for anything from jessie-backports.