To stay focused on the next update, Valve will activate all six of their previous Halloween updates this year instead of creating a new one.
Valve announced this in a blog post. There have been major Halloween updates every year since 2009, all of which will be revisited this year. More information about these events can be found at the Team Fortress 2 Official Wiki.
In the same post, Valve has announced that this year it will feature “a showcase of all the best Halloween-themed community content”.
“Over the next month we’ll be looking through the Workshop for anything tagged ‘Halloween’, so if you’ve been working on an item you think would be perfect, make sure you get it submitted and tagged before October 18th, 2015.”
While Team Fortress 2 won’t get its traditional new Halloween content, it seems that fans will still be given plenty to play with.