Yes, and that's why backwards compatibility is one of the most important things to WordPress Core development.
For a little perspective, there are dozens of WP Core committers, with hundreds of contributors working on WordPress Core full-time, all making sure that WordPress backwards compatibility is maintained and that updates don't break sites in a big way.
There are about 440,000 lines of code in WordPress Core.
s2Member Framework + s2Member Pro has about 315,000 lines of code.
It's no small task to maintain backwards compatibility or to produce releases with big changes that take into consideration all possible outcomes. Yes, s2Member powers a lot of online businesses and that's exactly why we take very seriously the responsibility of doing whatever we can to ensure that updates don't break sites.
Yes, within the next few weeks.