Subversion did not mean, that this piece of software do not work and is full of frustrating bugs. It may have some bugs, but it is a stable release version in development with some new features. This is why you can find nearly every second day a new SVN from roundcube. Today a better address book without bugs, next week a big nice great calendar with some graphical bugs... and hopefully a few days later, in the next SVN release, they are gone...
(Correct me, if I'm not right, but I think, this is pretty much the point.)