Have no fear!
We update our test server and run a check on each theme when a WordPress update is made. Then if there are bugs that appear in the latest update, we aim to fix them and release an updated version of that theme. You can then find details of the update in the changelog for each theme in our wiki documentation.
If for some reason you spot a bug that we haven’t, be kind as to let us know and we’ll take a look and strive to fix the issue :)