Most notable change is the deprecation of NetworkBehaviourEventProcess. See corresponding changelog entry on how to migrate.

Also rust-libp2p v0.47.0 updates to prost v0.11.0 which no longer installs the protoc Protobuf compiler. Thus to build rust-libp2p you will need protoc installed locally. On CI you can use the arduino/setup-protoc GitHub action:

- name: Install Protoc
  uses: arduino/setup-protoc@v1

For all other changes, see individual changelogs for details.