boolean revokeOldKey() {
        if (phase == KEY_DISTRIBUTION || phase == USING_NEW_KEYS) {
            phase = NORMAL_OPERATION;
            timestamp = System.currentTimeMillis();
            return true;
        }
        return false;
    }
Revokes old key by switching the phase to {@link KeyRefreshPhase KEY_DISTRIBUTION or USING_NEW_KEYS}

@return true if successful or false otherwise.
mesh/src/main/java/no/nordicsemi/android/mesh/NetworkKey.java