RBS850 Firmware problem V3.2.15.25 to V4.6.14.3

I have and RBK850 router and one satellite running well on V4.6.14.3 firmware. I bought an additional satellite which is running V3.2.15.25 and everything appears fine.Both satellites are connected to the router by ethernet. However, using the Orbi app I can see that the 'new' satellite requires upgrading to match the other. When I run auto update it shows 'upgrading ' but when it stops there has been no change. I have downloaded the latest version and was about to do a manual update on the 'new' satellite but read various threads indicating that this could result in problems. Before proceeding, please can you advise- should I first install as many of the 'missing updates -e.g.V4.6.8.5 as I can or should I go ahead and just install the latest version? Alternatively, as the system is working ok and the router is using teh latest version, should I just leave it alone? Thanks for your advice.