PhotonNetwork.player.NickName vs PhotonNetwork.playerName

[PHOTON]
whats the difference between PhotonNetwork.player.NickName and PhotonNetwork.playerName? Is it the same? If not, which one do I use for what?

The naming changed in the Player class but not in the NetworkingPeer and PhotonNetwork (mostly for compatibility reasons). Both values mean the same, which is a nickname that can change.