Getting references after a company closes, software tester here

I worry a reference will only confirm dates of employment. There are 11 people counting on me, so I am trying to be careful. I have one former client who liked my work. Who did you use?

I kept a note of my results so my references could be specific. They appreciated it.

Ask former colleagues and supervisors in a short message and give them a summary of the job you are applying for.