I'd be okay with an online activation check once a month. Most programs do that these days and everyone's online 24/7 anyway. In fact, I strongly recommend you do this if it means supporting the product and keeping it going. I've seen too many developers shut up shop because of piracy and I don't want yours to be next.
There hasn't been an update since May 23 now, which is very unusual. Hope everything is okay. Or maybe my complaint has made them slow down?