You have upgraded to ScanEngine version 5.2.8 and noticed there are some differences in how LiveUpdate works in this version, or have some problems with making configuration changes like configuring proxy service.
ScanEngine 5.2.8 introduced Java LiveUpdate (JLU) version 3.6. Please refer to How to change settings in Java LiveUpdate 3.6 or higher for assistance with configuration.
Please note: for the proxy settings to be honoured, you will need at least one entry in "Host Settings".
You might also find it useful to see how the liveupdate.conf looked like in ScanEngine 5.2.7 (JLU version 3.0). For reference, an example is attached to this article, below.