How to update a custom visual?

I have a report that makes use of the Infographic Designer (https://appsource.microsoft.com/en-us/product/power-bi-visuals/WA104380898?tab=Overview). The report uses version 1.6, but 1.7 came out earlier this year and I'd like to update (to resolve some performance issues which I raised through their issue tracker).

I've downloaded the new pbiviz file. When I open the file in notepad++ I can see that it says version 1.7.

When I open the report the tooltip for the visualisation says version 1.6. Time to update! I install the visualisation, agreeing to update the existing visualisation. The tooltip still says version 1.6.

Maybe update doesn't work? I close PowerBI without saving. I open the report again, delete the visualisation, then import the new visualisation. The tooltip says version 1.6.

Maybe delete doesn't work? I close PowerBI without saving. I open PowerBi, create a new report, and import the visualisation. The tooltip says version 1.6.

Given that the visualisation has the correct version number in it I can only assume that there is a cache of visualisations somewhere that needs to be cleared. Can anyone tell me how to correctly update the visulisation from 1.6 to 1.7?