I registered there because I had some altcoins listed only there. I forgot on my funds on there, now I just received an email from them about new required authentication. It's still possible to withdraw funds from there until the end of the 2019 year. So if someone else has funds on this exchange, you have a few days to withdraw it without KYC.
Dear STEX Customers!
We emphasize the necessity of your account verification.
Due to AMLD 5 since January 1, 2020 verification will be required for all the Customers. You can still use the platform without verification until December 31, 2019.
Make sure to familiarize yourself with amendment 5 to the Directive (EU)2018/843 of the European Parliament and of the Council (https://eur-lex.europa.eu/eli/dir/2018/843/oj).
Do not delay verification till the last day. Go online, get into your Profile and complete it on time!
I must say that I am surprised by his KYC authentication possibility. They provide a few other options to pass KYC using 3rd part service for that. Reduced potential misuse of personal data if this exchange was hacked.