Understanding Society User Support

Dear officer,

Hope you are doing well.

I have a question regarding the different SOC used.

I noticed in an explanation of variable "jlsoc90_cc", that it's said "In the first two waves of Understanding Society the description was first coded to the code frame of SOC 2000. From Wave 3 onward, job descriptions were first coded to the code frame of SOC 2010 and the code for earlier versions of the classification was computed from a look-up file". I wonder does this mean there's a clear mapping from SOC00/SOC10 to earlier versions like SOC90? If so, I'll appreciate it if I could see this look-up file. If it's not possible, could you please help me understand a bit more about the link/mapping between SOC90 and SOC00?

Thank you so much for your time!

Kind regards,
Peijie