Our enviroment is more like the same, Windows 2003 Server + Citrix PS 4.5 and all needed updates :
1200 – 5.2.0_60 > We have 4 off those but not using them anymore, we do have version 188.8.131.52 but never tested.
1125 – 5.2.0_53 > Works perfect, we have 184.108.40.206 (was develop on our request, but i think it is available for others aswell) This incl. ConnectionManager available when using Privilege=none / USB Readonly and timeserver fix. This is not based on ICA client 10.x
1150 – 5.3.0_20 > Works perfect, we have 220.127.116.11 (same as above develop on our request with the needed fix). I’m not sure which ICA version includes in 18.104.22.168.
v10L – 6.1.0_08 > Works perfect, but we are using 22.214.171.124 (only version 126.96.36.199 and above includes the ConnectionManager fix). Version 6.2.x includes ICA client version 10.x
Firmware updates at our company are done by using the FTP option.