The "Halloween update" you refer to wasn't new content, but content that was locked behind your computer's local time/date settings. It was the same exact content from the previous year, read that specific update blog and you'll see the dev say the same. If you still don't believe me, turn off automatic updates for your time/date setting and change the date to Halloween, it will enable that content again.
Viewing post in Hero's Harem Guild (NSFW +18) comments
No, GreyishGreen mentioned the Halloween update, which was simply a post mentioning it was that time of year and that the content was available to play again. I was simply pointing out that it wasn't an update to the game at all, and that it was simply old content being unlocked by your computer's time/date settings. See the dev's reply just before yours.
I'm not arguing that the last "update" post was about the Halloween content, that's an easily verified fact right now. And yeah, I can see why you're skeptical about unverifiable update news, as the game has gone for far longer than can reasonably be expected between updates to content. Did I enjoy playing through the currently available content? Absolutely! Am I holding my breath waiting for new content? No, not really. It would be nice if we did get new content, but I look at it the same way I look at getting tipped these days, it's always appreciated, but never expected.