What is a suitable substitute for sour milk cheese? I'm using it in a fondue. It calls for Harzer Cheese which I can't find locally. Thanks!

Harzer (Harzer Käse) cheese is a German sour milk cheese made from low-fat curd cheese, which contains only about 1% fat (such as cottage cheese).

From my research, it is a very strong-tasting cheese that is a very acquired taste and is often substituted for Limburger cheese. I'm not sure how it would substitute in a fondue recipe.