The 2.4.x.x versions of the installer fail with Delphi 11.3 but they work with XE and Delphi 12 (version 2.4.1.0 of course).
Done Building Project "C:\Users\David\AppData\Local\tmssoftware\registered\TMS Async\VaCommPkgDEDXE14.dproj" (Build target(s)) -- FAILED.
Version 2.3.0.2 does install into Delphi 11.3 without errors.