This document restates the requirements on DNSSEC signing and validation and makes small adjustments in order to allow for more flexible handling of configurations that advertise multiple Secure Entry Points (SEP) with different signing algorithms via their DS record or trust anchor set. The adjusted rules allow both for multi- signer operation and for the transfer of signed DNS zones between providers, where the providers support disjoint DNSSEC algorithm sets. In addition, the proposal enables pre-publication of a trust anchor in preparation for an algorithm rollover, such as of the root zone. This document updates RFCs 4035 and 6840.