UltraStudio Recorder and imac 2015 thunderbolt 2

A doubt that doesn't seem very clear to me on the websites the capture line and streming UltraStudio Recorder is compatible with iMac with thunderbolt 2

By my knowledge only the UltraStudio Recorder 3G is available, and that one is Thunderbolt 3 which isn't also USB-C.
So if you can get the old version you're in luck, if your 2015 imac is a Thunderbolt 2 model,Thundebolt 1 is also still compatible i understand, but only at the lower speed i guess.
btw..Mini DisplayPort looks also like Thunderbolt 2

Identify the ports on your Mac:
https://support.apple.com/en-us/HT201736