Tomas Nordin <tomasn@posteo.net> writes:

>
> sudo apt-get remove notmuch
> ... do the source install and re-run notmuch new. It will probably work
> smoothly with the setup I have?

We generally support upgrades but not downgrades. So you can move from
your existing setup to git master, but not necessarily back. You may
also face certain breaking changes in the emacs interface before the
next release.  We try to minimize those, but the nature of emacs means
we can't predict all the ways people have customized their environment.

And of course you're running unreleased software, so you can expect
somewhat less sympathy if things break. That said, most of the
developers run git master happily.