HA Setup - Active Passive

Question

Ok everyone, I am trying to get back to our HA setup and have a few questions. 
 We have 2 X XGS3100's, the Primary unit is active and currently registered and subscribed. I fired up the second 3100 today, now it is only connected back to the switch thru a fiber patch cable, no other connections. Both units were were shipped with SFOS 19.5.1 MR-1 Build 278 and I have not updated as of yet. 
 1) Should I update to the latest v20 before continuing with the HA setup? 
 2) The second 3100 (Auxiliary) only has a LAN connection so no Internet access, how can I register or even update? Temporary static routing? 
 
 Thanks

Erick Jan · Answer

Hi, 
 Thank you for reaching out to Sophos Community. 
 You don&rsquo;t need to upgrade to v20 immediately to establish high availability as long as you meet the requirements. 
 You may see the following requirements for establishing HA below 
 
 HA Requirements 
 About HA 
 
 For Firmware Update, you may do a manual upgrade. However, check the HA setup requirements. 
 
 Move to a different firmware version .