A couple of alternatives I can suggest:
1) Use an URL that contains a filter in it. For example:
https://www.snbforums.com/forums/asuswrt-merlin-addons.60/?prefix_id=10
2) Have one "master" thread, from which you can link to the latest release thread inside the first post. Even if that master thread ends up a few pages down the list, it would still allow people referred to it through an external link to quickly reach the latest release thread. That's a bit similar to how Voxel handles things (though he mostly just refer to the previous few builds), and also how Mozillazine handled release threads if I recall (posting a link to the previous thread).
3) Pointing directly at the sub-forum itself without a prefix filter applied, if you want one link for all of your addons (the new prefix system should make it easy to spot the important threads now that there is a dedicated sub-forum).
For now the route I went for my own documentation is to point at the AddOns subforum. I will probably use the first option of applying a filter for any application-specific link (for instance if someone asks me about Diversion itself through email or Twitter). I feel this method actually is the most user-friendly, because it allows users to quickly see all the available discussions related to the addon that interests them, not just the latest release.