Beware of upgrading from 7.x.x to 8.x.x when the RMX is in secure mode.
This article describes a problem with logging in after upgrade to 8.x.x when the unit is in secured mode.
If you performed the upgrade in one step, i.e. 7.2.2 -> 8.5.2 and your unit was in secure mode, i.e. you were able to log in only using HTTPS protocol, you likely to face a problem with logging in after the upgrade and restoring a backup of your configuration. There was a big change from 7.x to 8.x regarding cert management, it’s certainly better now. So the old certificate doesn't meet requirements of the new software and therefore can't be used, therefore you have to recreate it. You have only 2 ways to resolve it. 1. To perform a configuration form the scratch if your config isn't so complicated. 2. To wipe a configuration using appropriate procedure and rollback the RMX software to the previous version. Please note you can do only one step back, so if your upgrade path was 7.8.0 -> 8.1.x -> 8.5.2, you will be able to rollback only to the 8.1, therefore you can't restore the backup with security certificate properly. If you are lucky enough, you will rollback to the 7.X.X, then restore the backup and disable the secured mode. Then create another backup again and repeat the upgrade procedure.