Once Moodle release a new version it normally takes a few months for us all as plugin maintainers to make our plugins support that new version.
.And then make sure our plugin doesn't break with the updated version of any other plugins...
It is a bit like Jenga.
As Emma said -
Moodlerooms are the worlds largest Moodle provider with more clients and users than you'd care to think about.
Snap is Moodlerooms primary theme with a huge number of teachers, learners and organisations relying on it every day.
I'm no longer working with the Moodlerokms team, but i'm pretty sure Snap 3.5 is on their clients tests sites, and the fantastic team at Moodlerooms are getting it ready for Moodle 3.5
Moodlerooms normally update all their clients to the latest Moodle version twice a year - in summer and late December - similar to univesities i've worked in, so hopefully this gives you a timeframe.
Glad you like the theme, and appologies I cannot help in this instance.