Investigate freezing dependencies
In the past we have had a few issues that were caused by updated dependencies. For example #341 (closed) (Flask), #345 (pandas?) but also 86ae03f2 (Conda Docker) and I remember another issue with numpy.
A solution for this would be to freeze the version of all our dependencies. The downside is that we have to manually update the dependencies.
This issue is to discuss whether the advantages weigh up to the disadvantages of fixed dependency versions.