@umairhhhs Generally speaking, the official driver for Mac 10.15 will be released in a month after the official 10.15 OS version came out. Right now, Apple released the preview of the Mac 10.15 only....

@Vladek Thanks for your reply; with the 4G sim card put into the 3G modem, the connection can be 3G only due to the limitation of the 3G modem. Even though the TL-MR3420 supports 4G, considering it...

@AlexFr Thanks for your reply. You can give it a go and provide the information mentioned above so that we can do further analysis and try to fix it. Besides, if you have another SIM card, you can...

@Heero-Yui Hello, after you installed the firmware, please factory reset it not reboot. With the router powered on, hold the reset button/hole for 10s to hard reset it. Good day.

@GSPOT For your information, the Archer MR600 has 2 × Detachable 4G LTE Antennas. How do you put the outdoor antenna on? Does it replace one of the external LTE antenna? Good day.

@Bman.gnote Okay, check your message box. Nice day.