Sora RD compatibility

[Red Rider]

Is this RD able to take an 11-30t cassette (9sp)? It looks to be a medium cage...
Also, are the Sora HG50 and HG400 cassettes interchangeable?

Thanks

[Duck!]

No and yes.....

That 3400-series model is limited to 28T by its upper body geometry. The longer cage allows it the chain length to run with a triple-ring crank.

All 9-sp. cassettes, within relevant derailleur limitations are interchangeable.

[opik_bidin]

But wouldn't using a wolftooth link/ rear derailleur hook lengthener solve the problem?

[Duck!]

Or just use a newer derailleur with more capacity....