You can have an internal discussion with your IT team. You can understand the situation better.
Check these areas.
Once Qlik is made available outside our company domain the F5 (load balancer) will probably be able to provide additional SSL/HTTPS security configurations. Then this issue deserves a closer look and further investigation/action on how to handle/block TLS1.0 requests.
There is no explicit way to configure Sense into blocking certain request types (e.g. TLS1.0).
Browser, OS and .NET framework influence what cryptography systems use. Smart thing to keep them all updated. No immediate security risk, when TLS 1.0 is used.
Update the OS & browser versions on the machines that used to show the notification about obsolete cryptography is accepted as this moment.