Lost contract groups after upgrading to Skype 8

Hello,

I miss my old phone number groups in version 8. I had all the contacts (telephone numbers) sorted into groups in version 7. There were about 30 groups: Doctors, craftsmen, friends, family, other and about 24 other business groups.
In the new forced version, all phone numbers are designated as a single large pile. There are no more of my groups .. Only the term "all."
Does anyone know if and how I can reinstall these old groups?
I use windows 10 on a notebook.
For an answer I would like to thank you now!! :)