(1.) I have installed M1G HW venison .13, Boot Version 3.3.6, and firmware version 5.3.10, my ELK M1XRFTWM M1 Two-Way Wireless Transceiver is just bought.  Would I have any compatibility issues due to older firmware?  Id prefer not to update firmware and take risk unless you say its requried.

No need to update the M1 Firmware from 5.3.10 to support the M1XRFTWM however there have been a few changes in the 5.3.14 to help eliminate the System Start up log entries.

(2.) I see manual says I need to relocate by HW input expander on DB address 2 and its zones.  Can I simply goto HW IN Xpander adjust dip switches to DB address 11 then go into ElkRP (Ihave verion 2.0.40 for main program and M1/M1G Control Verison 5.0.40)  and then just renumber zones in 17 to 161, 18, 162, etc?  Do I need to do a bus enrollment or power cycle or anything like that as an intermin step?

That is correct the M1XRFTWM must start at Address #2 and you can up to a total of 4 M1XRFTWM’s  (Address 2,3,4,5) to the M1 Data Bus. You will need to re-address the M1XIN higher up in the addressing and reconfigure the new hardwired zones. I would suggest:

• Create the Hardwired Group in ElKRP2 — For Example Right Click on Zone (Inputs) and create New Hardwired Group 6 Zones 81 – 96
• Right Click on existing Hardwired Zone 16 and Paste it into Zone 81
• Repeat for Zones 18-32 into Zones 82-96
• Save the Changes
• Right Click on Hardwired Group 2 and Remove
• Right Cilck on Zone (Inputs) and create Wireless Group 2
• Configure Wireless Zones 17-32
• Save the Changes
• Readdress M1XIN from 2 to 6
• Set the Address of the M1XRFTW to2
• Perform the Bus Module Enrollment
• Verify M1XRFTWM is Address #2 and M1XIN is address 6
• Send Zones and Test each Zone

(3.) with the zone number chnaging I wonder what will all break.  I notice in Home assistant and in ISY both seem to refer to zone name and not number.  Any ideas here?

After making the changes in the M1 you will need to resync the other Home Automation platforms.

(4.) Now onto databus wiring.  I have ordered a DB Hub Retrofit style but it wontcome for a week.  In the interim I was going to run a 3rd home run in to the M1G databus from the wireless transceiver and not terminate it.  If push came to shove I could disconnect one of the keypads until hub comes in.  If I did not disconnect anything and had 3 home runs with the new one being the 3rd with unterminated ELK M1XRFTWM, would I be able to operate with some occasional comm loss errors?  Any chance it could work fine.  Run lengths are relatively short.  My only concern is comm would be soe bad I couldn’t enroll the transceiver or wireless sensors.  Any thoughts here?

The M1’s RS485 Data Bus will support two home runs and if attempting a third you could have bus issues with Missing Expansion Modules or delays when zones change state and so forth. I would suggest waiting on thge M1DBHR Data Bus Hub Retro Fit .