1. A method for execution by a storage unit of a dispersed storage network (DSN), the method comprises: transitioning storage of one or more groups of encoded data slices from storage based on a previous version of a distributed agreement protocol to storage based on a new version of the distributed agreement protocol; and while transitioning storage of the one or more groups of encoded data slices: receiving a proxied data access request regarding an encoded data slice from another storage unit of the DSN; determining whether the other storage unit is an authentic storage unit of the DSN based on at least one of: the encoded data slice, the previous version of the distributed agreement protocol, and the new version of the distributed agreement protocol; when the other storage unit is the authentic storage unit, processing the proxied data access request to produce a data access response; and sending the data access response to the other storage unit.