The zip file contains ExtIO plugins for RSP1, RSP1A, RSP1B, RSP2/2pro, RSPdx & RSPdxR2 (excluding HDR mode) and RSPduo (excluding Diversity mode)
The RSP1B requires as a minimum: API 3.14
The RSPdxR2 requires as a minimum: API 3.15
Go to https://www.sdrplay.com/api to download the API