What Does User-Activated Soft Fork (UASF) Mean?

A user-activated soft fork (UASF) is a specific kind of divergence in a bitcoin or cryptocurrency chain. The fork leads to a lack of consensus in nodes, which may be resolved at a later point. It has interesting applications to the ongoing administration of a cryptocurrency model.

Techopedia Explains User-Activated Soft Fork (UASF)

Experts in bitcoin and other cryptocurrencies sometimes describe a soft fork as “backwards-compatible” or as a phenomenon where older rules can be replaced in a less strict way, with an “opt-in” for stakeholders, although at a future time, miners may be at risk of creating invalid blocks. Further, a user-activated soft fork is one that is predominantly driven by user activity, not by miners or other parties, and which miners will generally be compelled to follow.