There are installers for all supported Delphi versions (including 10.3 Rio), take your pick:
- GXRS10.3-13C-experimental-twm-2018-12-22.exe
- GXRS10.2-13C-experimental-twm-2018-12-22.exe
- GXRS10.1-13C-experimental-twm-2018-12-22.exe
- GXRS10-13C-experimental-twm-2018-12-22.exe
- GXRSXE8-13C-experimental-twm-2018-12-22.exe
- GXRSXE7-13C-experimental-twm-2018-12-22.exe
- GXRSXE6-13C-experimental-twm-2018-12-22.exe
- GXRSXE5-13C-experimental-twm-2018-12-22.exe
- GXRSXE4-13C-experimental-twm-2018-12-22.exe
- GXRSXE3-13C-experimental-twm-2018-12-22.exe
- GXRSXE2-13C-experimental-twm-2018-12-22.exe
- GXRSXE1-13C-experimental-twm-2018-12-22.exe
- GXRS2010-13C-experimental-twm-2018-12-22.exe
- GXRS2009-13C-experimental-twm-2018-12-22.exe
- GXDelphi2007-13C-experimental-twm-2018-12-22.exe
- GXBDS2006-13C-experimental-twm-2018-12-22.exe
- GXDelphi2005-13C-experimental-twm-2018-12-22.exe
- GXD7-13C-experimental-twm-2018-12-22.exe
- GXD6-13C-experimental-twm-2018-12-22.exe