I have installed mender-client v4 on an arm device and recognized that the private key generated by the mender client is of type ED25519. I need to use a RSA key. Is there a way to configure the algorithm the client uses for generating the key file?
You can not customize the “automatic generation”. However I would recommend you to create your own and provision it. In that case, the Mander client will not create another one. More information in Security | Mender documentation.
You can even be more specific on what is used for Authentication and for the SSL handshake: