I’m trying to install on a 2011 MacBookPro. So Metal isn’t supported. The last version of UE that doesn’t absolutely require Metal appears to be 4.14.3.
I clicked on “Add versions” in the Library tab of Epic Games Launcher - but it only offers me 4.16.3 (in addition to 4.17.2).
You can use the GitHub Repository of Unreal to check out the Version you want and then compile it.
Its quite easy to create a self-compiled Editor version.