How can install UE 4.19?

From the epic games launcher, on library pane, I can install UE 4.21.0 or UE 4.20.3. If I select the +button, there are no other engine versions available.

If I go to Unreal Engine 4.19 Released! - Unreal Engine and select download, I get errors, even after I removed the epic games launcher.

in the epic launcher, in the unreal engine tab, go to the library section. there you will see under engine versions one that is grayed out which probably says 4.21, click the down arrow next to the number and a list will come up of all engine versions (see yellow arrow in picture below). just click the version you want then click install.