If you own a Kontakt 5 license (purchased before Kontakt 6’s release), log into Native Access. Go to "Not Installed" and find "Kontakt 5." Click the dropdown arrow next to the install button. You should see an option for "5.5.2" (or 5.6.8, the very last 5.x). Choose 5.5.2.
Are you still running older versions of Kontakt for specific libraries? Let us know in the comments which version is your favorite "reliable old faithful." kontakt 5.5.2