  This article is about temporal multi-agent logics. Several of these
formalisms have been already presented (ATL-ATL*, ATLsc, SL). They enable to
express the capacities of agents in a system to ensure the satisfaction of
temporal properties. Particularly, SL and ATLsc enable several agents to
interact in a context mixing the different strategies they play in a semantical
game. We generalize this possibility by proposing a new formalism, Updating
Strategy Logic (USL). In USL, an agent can also refine its own strategy. The
gain in expressive power rises the notion of "sustainable capacities" for
agents.
  USL is built from SL. It mainly brings to SL the two following modifications:
semantically, the successor of a given state is not uniquely determined by the
data of one choice from each agent. Syntactically, we introduce in the language
an operator, called an "unbinder", which explicitely deletes the binding of a
strategy to an agent. We show that USL is strictly more expressive than SL.
