Highend stuck on General Settings, can’t update

I recently updated WordPress and now the Highend theme is broken. I first noticed all FAQ and toggle boxes on the website are broken/expanded with the frame missing, and also the Highend options page is stuck on General Settings (and the settings cannot be changed.)

I see a few others here with the same issue it seems, and updating may have fixed it I cannot tell from the replies, but I haven’t updated Highend in ages because there are never any updates for Highend when I check in WordPress Updates section. I am running version 2.4.4 and I know you are at 3.x.x – how can I update?