exists folder “C:\Program Files (x86)\F5 VPN”
1st you are trying to look for folder for your related app but on other side you are trying to do opposite search not exists key !!! are you sure that folder will exists but key will not ?
OR may be since you are trying to just upgrade your app with different service name.
not exists key “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\F5InspectorService}” of registry
apart from that you have curly bracket in your 2nd registry key lookup, you need to correct that.
if your service is listed already in services you can simply do something like -
not exists service "F5InspectorService" whose (version of it >= "1.0.1") (for install & upgrade both)
not exists service "F5InspectorService" (for install only)
For this you need to check the available switches within your installer like with MSI we have /qn /norestart