@268BBA hmmm, that was strange. I have exactly the same solution, ER8411 and SG2428P switch but have never noticed that WAN drops. Are you using L2TP VPN then? I have noticed that there can be drops...

@268BBA Do you use IPS/IDS?

@GRL you can do a roll_back and then upgrade

@GTT-IT NO, you have to make everything from scratch.

@NovaSistemas I also use an ER8411 and experience the same thing, I had to turn off DNS in the IPS configuration, after I disabled DNS I have not had any problems with IPS,

@MR.S It doesn't look like it works in stand alone, in stand alone you can only add an IP network to the client configuration. you can add on server but not client, If you use omda controller you can...