Cant help you there.. I have copies of firm ware back to 2.51 but not earlier.. I assume 2.33 uses quite different protocols and programming than the later versions as 2.33 is not compatible with newer versions.

The Rxs should load the earlier version of firmware, you will just need to have the right versions of Giga-control and update software. Fortunately Weatronics provides a Release History document which details all the different firm/soft ware versions, and what they are for and compatible with.

Probably not a bad idea to stay with 2.33 if it does everything you need..

Roger