I used my WavePay accounts in my two devices. I upgraded to version 1.4 and authorized one device first and my account in the other device logged out, is there a way to log in in that device again?

In this case, you can upgrade WavePay version to 1.4 in the other device and can log in again to request to the primary device to authorize your other device. But pls note that, you can use your WavePay account in one device only.