st.experimental_get_query_params() recently stopped working on Streamlit Sharing - it returns empty dict. The same code works well on Heroku and local machines.
Finally figured out the issue: the github repository name had a ‘-’ and I had to remove it to fix the problem.
The url must still include the branch name: repositoryname/?var=val won’t work. repositoryname/branchname/?var=val must be used