The "reflist.ref.old" files are safe to delete. They are created as a backupfile each time a new update is made and they aren't necessary. The new "Reflist.ref" contains all the data required.
Hope this helps.
I use Easy Cleaner by ToniArts and when running it to check for unnecessary files, the reflist.ref.old files show up. Is it safe to delete these files or do they need to remain on hard drive like the updates to AVG do? Thank you.