Ask HN: How do I (USA) know if it is legal to work with my Russian clients?

I live in the USA and have licensed software (that I wrote) to a few Russian companies, and I periodically interact with them for support issues. My software isn't anything that would be considered "controlled" class software (e.g., crypto). However, I don't know how to tell if I am violating any sanctions. Where would I go to find out if I'm running afoul of some new restrictions?