@Kevin_Z   Thanks for the confirmation.  I have tried the [201204-rel66940] firmware and carried out some tests.  The band selection appears on the Basic page of the MR600 V1 management, and the function of selecting the band works well.   My use case was to discover if carrier aggregation would work on the same band (Band 3) with the MR600 by manually selecting bands 3,3.  Answer is yes and no.  Yes, bands 3,3 can be selected, but the service then falls back to 4G (not 4G+ LTE-A) and both DL and UL speeds deteriorate.  On my mast, Band 3 is 15MHz and Band 20 is 5MHz bandwidth.  I am getting 45Mbps DL and 25Mbps UL with CA (4G+) and 35MBps DL, 17MBps UL with manual 3,3 selection (which MR600 reports as Band 3, 4G).  Not sure if any affordable router could provide CA on an intra-band FDD signal (even if possible within 3GPP since Release 10).  Maybe you could run this past the development team??

So conclusion for now is I will stay with auto band selection, which gives me the best real-world performance.

The SMS inbox is now working.  The fix really must be released asap in an official firmware.  Otherwise the product does not work as intended/described.

rel66940 Beta on MR600 has issues with the correct positioning of the background page colours (white over cyan) behind the text, needs some tweaking before any official release.   In most cases, the white background does not reach the bottom of the page text (e,g. see Advanced/Network/LAN or Advanced/Status)

[Edit 04 Feb 2021 10:30GMT]  I should add that in case anyone is curious about those DL/UL speeds, I am using an external Iskra P58-L700 antenna with direct line of sight to the transmitter at 5km.  Router stats typically Strength 100% ; RSRP = -80dBm; RSRQ = -11dB; SNR = 15 dB.  With the integrated rabbit ear antennae in an upstairs Velux window with trees blocking direct line-of-sight, speeds were only 30-50% of the figures above.  

Also reading up on Carrier Aggregation, it seems that the maximum aggregated bandwidth for 3,3 manual selection is either CA_3B (B3+B3) at 10MHz or CA_3C at 40 MHz.  So with Auto selection 3,20 I am seeing the full potential of CA_3A-20A (B3+B20) aggregation which maxes at 40 MHz (or 15 MHz + 5 MHz = 20 MHz with my mast), and maybe the B3+B3 is somehow implemented differently with my mast / cell / router combination.   Although I saw very little difference in the router stats, RSRP, RSRQ etc,   CA info here  https://halberdbastion.com/technology/cellular/4g-lte/lte-carrier-aggregation 

[Edit 04 Feb 2021 11.05GMT]  I see the CA combinations for MR600V1 in this thread https://community.tp-link.com/en/home/forum/topic/219080?page=2

Which seems to suggest that CA_3C with max aggregated bandwidth of 40MHz should be possible (which would best my 3,20 auto selection of 5+15 MHz bandwidth), but my MR600 only reported 4G LTE with 3,3 manually selected.  Now unsure what's happening when I manual select 3,3.  Maybe try it again when I get time.  

I bought my first TP Link, and I'm very disappontead.

You announce Dual band select 4G+ and the product doesn't have it. I think this could be considered a scam.

Hi, I recently bought an Archer MR600, and i'm a bit disappointed to be forced to use a beta firmware in date of December.. Only for............... read my SMS !

This beta firmware give me the possibility to read my messages, OK, but it is not stable at all, and make my router stuck at least one time a day, so I have to reboot it manually by disconnect/reconnect the power cord.... (Not comfortable at all...)

Does this firmware include the last security updates, as the last official one ?

When will we have an official release ? Is it ok to not have any official fix since (soon) a year (just for some minors bugs) ?

Last one was from June 2020....

Thanks.

@Kevin_Z thank you for the beta firmware updates. may i kindly ask if there's an official update release plan?

@Kevin_Z 

Does this v1.1 beta include the security patches of the stable v1.2 firmware?

@Kevin_Z 

I updated my mr-6400 v5 with this beta firmware, and set the lte band manually to 7.

Unfortunately disconnections issues remains, as after 2/3 days operating correctly whenever I try to connect with my smartphone I get kicked out from WiFi after a couple of seconds. At the same time other devices are reporting connection issues with internet (cannot reach a remote server), but internet connection is reported to be ok from the router panel and leds. Mr6400 also reports the devices under its "wireless client" list. Same devices connected to another router (same room, different brand, much smaller antennas) do not show this behaviour.

The mr6400 is set to self restart at 3 am, which sometimes solves this situation, until the next happens again.

I kindly ask if tplink can provide a solution, otherwise I will have to return the router as fundamental functionalities are not working properly.

Thank you