Killing Floor 2 is nearly three years old, but despite this has enjoyed continued support from it's developer, Tripwire Interactive, during that period of time. It seems now, though, that the company is going to have to start offering paid DLC in order to be able to continue supporting the title.
In the past the company has offered lots of free DLC content, such as the Back and Kickin' Brass update. It seems though that offering things for free isn't a great way to make money. (tell us about it...)
The company stated in a post on Steam;
As we have looked at the life cycle of the game, we strived to look at new ways that will enable the game to live on and grow well into the future. With where we are with the project, we know there’s a hungry desire for everything featured in Killing Floor 2. While the updates have all been free in terms of features, weapons, zeds, maps, etc, the cost of development has certainly been anything but, ultimately, that status quo of our current strategy cannot sustain the current level of support that you have all grown accustomed to without a major shakeup.
According to Tripwire, they could either have basically cut the content included in each update way down to basically bug fixes and minor updates, or find a new revenue model to allow support for the game to continue as gamers are accustomed too.
While no doubt the concept of paid weapon DLC will be met with outrage by some, it seems like a fair trade-off to continue supporting such an old game - something has to pay developers wages, after all.
The company have promised any DLC weapons will not be better than any equivalent weapon available in the game, but may provide unique gameplay experiences or "fill new roles within the arsenal that are not already served" - whatever that means. Free weapons will still continue to be added in future updates too, though, and paid weapons will work with the Shared Content System, so if a player on a server has a paid weapon, all other players also get access to it.
Modding will also be preserved, too, which we are very happy to hear, with the company promising to continue to support modding and add new hooks to the game for modders to take advantage of in the future.