I am a new developer and not particularly familiar with the project I'm asking about but want to get some feedback regarding ideas at this point.

There is an online chart with diagrams linked to other pages that was created with a very old version of MS Visio. The diagramsare no longer displaying parts of the charts (text or other elements) in newer browsers.

Do you have ideas for fixes for this without buying an updated version of Visio?

Thank you!