I wouldn’t use the second one that you gave a link for, just look at the path, it is a ‘custom’ build so shouldn’t be used unless A) you know what has changed, the circumstances/reasons for the build and B) your situation matches the requirement for a custom build.
“Unfortunately” I already ran the installer in the second link. I was also surprised to see that strange path, that’s I’m writing here. If you go to avast.com to download the free antivirus, you’ll see the download link won’t be “files.avast.com/iavs9x/” but “files.avast.com/files/custom/tpmo6552/”. That’s strange.
It is certainly strange - what build number does it show for the installation ?
The stub installer is a somewhat different case to the full off-line installation file, the stub installer would go and grab the latest avast version and start installing it. So in theory it should end up with 2015.10.2.2215 installed.
I would never use the on-line installation file, if you had another AV installed you should uninstall it or you could have conflict issues. If you did uninstall it, then effectively you would be going on-line without protection whilst you install avast.
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