ESA Doctor's Letter Requested

Hello, I wonder if anyone can help.

I'm on DLA (still not switched to PIP and ESA).

Last year I had an assessment for work and was put into a support group.

I'm on the higher rate for everything.

Today I had a letter from the DWP requesting a doctor's note that I am still not fit for work. I've never had that before. Is this a new thing, or normal now.

Thank you

That's really appreciated cheers.

I rang and it seems to be sorted, I will ring back next week to make sure.